The University of Arizona

Category | CLIMAS


Beginning to Understand Climate Change in the Kaipara Catchment

Thursday, September 14, 2017

I’ve tagged along on environmental monitoring patrols, ridden in logging trucks with forestry workers, played cow wrangler on a dairy farm, photographed coastal erosion from the back of a four wheel drive that smelled of turkeys, and attended a conference on the wellbeing of eels. I’ve had conversations on boats and beaches, in fields and farmhouses, by lakes, in rivers, cars and marae (meeting houses). This is what happens when an anthropologist is on the case.

Figure 1: Here I am pictured on a river monitoring trip with Millan Ruka of Environment River Patrol-Aotearoa. Photo courtesy of D Clarke.

This summer, with the help of a CLIMAS Climate and Society Fellowship, I have had the chance to work with a fantastic group of people in the northern Kaipara Catchment of Aotearoa (New Zealand) to investigate the impacts of climate change on communities in the region. This research project grew out of conversations that were initiated in June 2016 between myself and the Integrated Kaipara Harbour Management Group (the IKHMG). The IKHMG is a Māori led, multi-stakeholder group working toward the restoration and collaborative, holistic management of the Kaipara Harbour and Catchment, that encompasses 640,000 hectares in the Auckland and Northland regions of Aotearoa. Alongside priorities such as regenerating native biodiversity and working towards the inclusion of mātauranga Māori (Māori knowledge) into management frameworks, the IKHMG is very interested in expanding its understanding of how climate change will affect communities throughout the catchment, and helping them to prepare for and adapt to these impacts. 

Climate change is predicted to bring increasing temperatures, less rainfall, more drought, intense rainfall events, pests and diseases, rising sea levels and ocean acidification to the Kaipara Catchment. Because the natural environment of the Kaipara is an integral part of many people’s identities, livelihoods and wellbeing, climate change has the potential to seriously affect communities in the area.

Figure 2: Map to show the location of the Kaipara Catchment

There is currently a lack of research into the socio-economic, health-based and cultural impacts of climate change in Aotearoa, and attention is generally more focused on higher-level climate change mitigation efforts than grassroots, community-led adaptation. Although a few studies do exist in this space, no such research has been conducted in the Kaipara, meaning that there are few guidelines or models for groups like the IKHMG to turn to. In order to begin to address this research gap I proposed last year to the IKHMG that I structure my Master’s research around climate change impacts and adaptation in the Kaipara Catchment. Since then, I have been working to bring this project to fruition: designing the research questions and protocols in collaboration with the IKHMG, drawing upon the expertise of CLIMAS personnel during planning meetings, taking a class in climate science, reading about climate change vulnerability and adaptation, and of course, making funding applications.

Between mid May and the end of July 2017, I conducted fieldwork in the northern part of the Kaipara Catchment. The research sought to assess community members’ understandings of climate change, their perceptions about how climate change may affect their lives, what they feel should be done to address these effects, and whether any opportunities are associated with impacts or adaptation efforts. Drawing on the invaluable experience that I have gained through working as a Research Associate with the University of Arizona’s Bureau of Applied Research in Anthropology, I engaged in many hours of structured observations, held 34 semi-structured interviews, and facilitated a community hui (interactive meeting) on climate change. These activities allowed me to gather information from a total of 76 people in the Kaipara. Because this research is, at its heart, about and for Kaipara communities, I made a point of inviting feedback on research questions, directions and outputs from both the IKHMG and community members with whom I spoke.

Figure 3: Participants at the Climate Change hui, held at the Otamatea Marae in June 2017.

Although I am only in the early stages of analyzing the data I gathered over the summer, I would like to briefly share some of the larger themes that have emerged.

In the Kaipara Catchment, many community members have concerns over issues such as freshwater and marine contamination, the decline of native biodiversity through land use change and pests and diseases, rural depopulation, lack of employment opportunities and financial security, and the loss of local knowledge systems, which have already placed pressure on community wellbeing. While climate change may not be at the forefront of many people’s minds, community members have noticed changes in weather patterns and environmental conditions, and for many, future climate change will interact with the issues mentioned above. In the Kaipara Catchment, the impacts of climate change will not happen in a vacuum; they will play out against a background of ongoing socio-political, historical, and environmental processes. 

My current understanding is that climate change will ultimately place further stress on community wellbeing, whether from the perspective of physical, mental and spiritual health, economic security, or socio-cultural identity.

To take just one example, many community members have concerns over the quality and abundance of kaimoana (seafood) such as shellfish in the Kaipara Harbour and coastal waters. These concerns are believed to be related to contamination of freshwater systems from colonial land use change, intensive agriculture, forestry, and sand extraction operations, and restriction of access due to private land ownership, overfishing and quota allocation. In recent years, worries over access to shellfish have intensified with higher than normal summer temperatures and increasing coastal erosion from sea level rise causing declining abundance and quality, and flooding of low lying roads making travel to shellfish beds difficult. In the future, more storms may lead to increasing contamination of shellfish with pollutants from higher in the Catchment, warmer temperatures may intensify the risk from pests and diseases, and ocean acidification may add further complications for shellfish survival.

Shellfish are an important resource for many coastal communities around the Kaipara. Many community members live in rural areas, where access to food stores, employment opportunities, and even unemployment benefits are restricted, meaning that shellfish is a key source of protein in the diet. The ability to share shellfish within the community, at hui, and with visiting whānau (family) and friends is also an important part of Māori culture, protocol, identity and knowledge systems that is already under strain. In addition, some community members’ livelihoods depend on small and larger scale aquaculture ventures. Climate change, then, may magnify existing concerns over wellbeing that are related to food security and physical health, the erosion of cultural identity, knowledge systems and protocol, and economic prosperity.


Figure 4: Sedimentation in the Kaipara Harbour is one of the ongoing threats to shellfish health that may interact with future climate change.

Figure 5: Coastal erosion presents another challenge to shellfish health in the Kaipara Harbour. Photo courtesy of Maree Jones.

Another suite of impacts relate to intensification of existing pressures on mental health and financial wellbeing. For example, many farm owners and workers in the Catchment already face challenges with isolation, stress, and a lack of financial security and independence. These may be increased with more droughts, floods, heavy rainfall events and pests and diseases in the future, as a result of needing to increase spending on infrastructure and farm resources, and potential loss of stock, crops, and employment.

Understanding the ways in which climate change will interact with existing processes and issues in the Kaipara is key in developing meaningful pathways to adaptation. Many people with whom I spoke emphasized that working to adapt to the impacts of climate change presents opportunities to address a wider network of issues – such as freshwater and Habour health, economic security, and lack of community representation in decision making – which are deeply intertwined with, and often at the heart of, the impacts that communities will experience. Successfully adapting to climate change in the Kaipara will involve engaging with these processes, to create environments and communities that can withstand the additional pressures that climate change may place on them.

Many interviewees see Catchment-level restoration as a key component in building the capacity to successfully respond to climate change impacts, such as the shellfish example discussed above. This will need to take place at a variety of levels and include a diversity of voices. Community, marae or school-level freshwater monitoring and environmental education programs, for example, may combine with collaborative ventures between communities, government and the dairy or forestry industry to encourage or legislate for riparian planting, exclusion of stock from waterways, and trapping sedimentation run-off. 

Figure 6: Encouraging Catchment restoration through activities such as riparian planting is a key part of working towards climate change adaptation for many community members.

Increasing farmer resilience to climate change is also an important theme that has emerged. Many interviewees suggested that mentoring programs may help farmers to alleviate mental health stress, and build their financial capacity to invest in infrastructure and withstand potential losses, while collaborative research and networking can assist farmers to experiment with new crops, stock, or techniques that stand up to changing climatic conditions.

Figure 7: Helping farmers build capacity to respond successfully to events like floods and droughts is another priority for communities in the Kaipara Catchment.

It has been heartening to witness the level of engagement of the IKHMG and other community members in this research project. Everyone that I have spoken to has been very generous with their time and knowledge, and I have been afforded some truly unique experiences by some of my interviewees. The research has even been featured in two local newspapers. You can read the stories here:,

Over the coming months, I will be working to write up my Master’s thesis, and produce a summary document for the IKHMG that will outline the main findings of the research. This document will be used by the IKHMG to help prepare communities for future climate change, by supporting adaptation measures. Although I have lived and breathed this research project for the past three months, I feel that I have only begun to scratch the surface in terms of understanding the complexities of climate change impacts and adaptation. In the coming months, I will be developing my PhD dissertation research proposal to continue working on climate change in the Kaipara in partnership with the IKHMG.

Figure8:  Beautiful Pouto Peninsula in the Kaipara Harbour

I am very grateful to CLIMAS, the Social and Behavioral Research Institute, the Graduate and Professional Student Council and the IKHMG for supporting this research. I would like to say a very special thanks to Willie Wright and Jane Worthington of the IKHMG, Shaun Awatere of Manaaki Whenua, Millan Ruka of Environment River Patrol-Aotearoa, and Dylan Clarke of Auckland Council for all their help, guidance and support along the way. Kaipara Ora!

You can read about the work of the IKHMG here:

Climate and Water Resources of the Chuska Mountains

Monday, September 11, 2017

In the fall of 2015, I began working with the Navajo Nation Department of Water Resources, Water Management Branch, to address water resource management questions they had for the Chuska Mountains. These mountains are the only native headwaters on the Navajo Nation, where water scarcity impacts Navajo tradition, culture and livelihood. Since our initial discussions, Water Management Branch staff and I have collaboratively developed guiding research questions about past changes in water and climate.

Our first field expeditions explored the landscape of the Chuska mountains so that I could better understand this unique place and its importance to the Navajo people (Photo 1). My guides were Carlee McClellan and Irving Brady from the Water Management Branch and Crystal Tully-Cordova and Lani Tsinijinni, both Navajo PhD students working on modern water in the Chuska Mountains.  They helped me stitch together an understanding of this hydroclimatic system, as well as help me visualize Navajo agricultural and traditional ties to the place.

My project is guided by the Navajo water managers’ interests and concerns. My research background drives our approach to investigating their questions. For this reason, I am following a two-prong strategy to try to answer questions of snow and surface water changes in the past. First, I am using tree rings and Navajo snow records to reconstruct Chuska snowpack prior to the last 30 years of instrumental records. Second, I am using satellite imagery to develop a baseline record of surface waters in the Chuskas for the last 30 years.


Photo 1  Navajo Water Management Branch field technicians Irving Brady and Ralphus Begay collect streamflow data for Whiskey Creek, Navajo Nation
Photo 2 Irving Brady demonstrates the use of a snow corer to sample snow pack. Snowpack snow water equivalent is determined from the weight of the snow sample in the tube. Staff at the Water Management Branch collect these data bi-monthly from January to April.

Gaining a Long-term View on the History of Snow

After initial analysis of the relationship between regional tree-rings and Chuska snow, it became clear that a strong connection exists between climate information contained in the rings and Chuska hydroclimate itself. This connection can be exploited to reconstruct past hydroclimate. However, to take advantage of the limited time period covered by the snow data, we concluded that we needed more current tree-ring records (Photo 2).

In January, buoyed by support from the Climate and Society Fellowship, I planned a field campaign to collect tree samples on the Mogollon Rim in northcentral Arizona. The goal of the field campaign was to update sites that showed a strong relationship with Navajo snow, and to supplement tree-ring records currently under development collected from the Chuskas. The Mogollon Rim experiences similar winter weather patterns as the Chuska Mountains. These patterns are reflected in regional SNOTEL and snow course site records. The existing Mogollon Rim tree-ring records were too short to cover the last three decades, an important hydroclimatic period because it overlaps with the Chuska snow data and because it captures a period of known hydroclimatic extremes in the region.

I felt excited anticipation about conducting fieldwork in higher elevations in winter, yet unsure about temperatures and snow depth. These uncertainties weighed on my mind as I traveled to Tucson to collect increment borers, sample straws, GPS units and, most importantly, my invaluable field crew Dr. Paul Sheppard and Alex Arizpe, from the Laboratory of Tree-Ring Research (Photo 3). Our destination was the area around the San Francisco Peaks, Arizona, where dendrochronologists collected tree-ring samples in the 1980’s. Our mission was to return to these notable sites and core new trees storing information for the last 30 years.  Our first stop was a pinion-juniper woodland near Sedona, Arizona, under overcast skies following a day of rain but no snow. The pinion trees were young and middle aged. This would be our only time in the more arid setting typically found with the pinion-juniper forests because the next three field sites were in the dry, park-like Ponderosa pine forest around Flagstaff, ARizona. We cored Ponderosa pine trees at Sunset Crater, Robinson Mountain nearby, and further to the west at Slate Mountain. Our final stop was snow-covered and at higher elevation in the cooler, denser Douglas fir forest of the San Francisco Peaks. There we found the snow and needed to post-hole in thigh-deep snow looking for promising trees to core.

Our two-day field campaign was successful! We returned to Tucson with 107 tree cores from 55 trees and 5 sites (Photo 4). Though I am still finalizing dates on the rings, at least one core dates back to 1636.  Mounting, sanding, counting, dating and developing an updated site chronology for each site is now nearly completed. Soon, these chronologies will be ready to use as potential predictors in a snowpack reconstruction model (Photo 5).


Photo 3 Becky Brice, Alex Arizpe, and Dr. Paul Sheppard stopping at Sunset Crater to collect tree cores, and photographs. 
Photo 4 We collected over 100 tree-ring samples from the Mogollon Rim, Arizona.  Dendrochronologists use increment borers to extract pencil-sized cores from trees (blue tubes). In the field, we place the fragile cores in rigid straws for transportation to the lab (white tubes). Once at the lab, we mount and sand each core for dating, measuring and analysis (wooden sticks at left).
Photo 5 Regional map of northeastern Arizona, including the Mogollon Rim near Flagstaff and the Chuska Mountains of the Navajo Nation. Blue dots show the location of snow course and SNOTEL sites. Purple dots show the location of tree-ring climate  sites used for this study. Green dots are existing tree-ring ecological sites collected by Christopher Guiterman.

Watersheds and Lakes of the Chuska Mountains

Surface waters in the Chuska mountains seem to be an indicator of hydroclimatic variability. The relationship between snowpack and surface waters is a pressing question for Navajo water managers, particularly if this relationship will help them better understand mountain runoff and water supply. However, streamflow records are limited in the Chuskas, and no lake level records exist for the naturally occurring lakes. In response to these basic data needs, my collaborators and I investigated approaches to quantify surface water changes.

To reconstruct a record of changing lake surface area, we decided to use satellite imagery and focus on three of the largest naturally occurring surface waters (Photo 6). Following my initial evaluation of lake levels in the Chuska Mountains, two goals emerged. The first goal was to have a way to accurately quantify lake area. I decided to walk the perimeter of at least one lake to ground-truth lake area estimated from satellites, versus lake area measured with GPS. The second goal was to visit the study area with a focus on watershed scale, location and orientation. How does the surface water run off these mountains, and then reside, anyway? I returned to the Navajo Nation in June to accompany Irving Brady, a Water Management Branch veteran of nearly 30 years, to view the watersheds. Irving has become an essential source of expertise and guidance for understanding the cultural landscape in this traditionally important mountain range, as well as for understanding the physical landscape itself. Data collected from this field trip is still being compiled and evaluated. I’m optimistic that it will help us further define and our understanding water resources in the Chuskas.

Photo 6 Toadlena Lake in the northcentral portion of the Chuska Mountains. Toadlena Lake is one of three lakes with estimated surface area using satellite imagery.

Ongoing Collaborations with Navajo Water Managers

Collaborating with the Navajo Nation has proven to be intellectually and professionally invigorating.  Partners at the Navajo Nation Department of Water Resources are supportive and have facilitated entry to essential locations in the otherwise hard-to-access Chuska range. Steep, loose and narrow forest roads necessitate an expertise unique to members of the community.

As a reciprocal effort, I have been actively sharing progress of my research through professional talks co-authored by collaborators at the Laboratory of Tree-Ring Research (LTRR), Dr. Christopher Guiterman and Dr. Connie Woodhouse, and Carlee McClellan at the Water Management Branch.  In April, I shared preliminary results during the University of Arizona’s Earth Week. Colleagues at the Laboratory of Tree-ring Research, enthusiastic about this study, introduced me to new ideas and potentially different approaches to my research.  I also shared these preliminary results at the Association of American Geographers Annual Meeting, Water Resources Specialty group in Boston. My colleagues in geography expanded my thinking even more broadly to thinking about the cultural landscape in combination with the physical place.

In May, I returned to meet with staff at the Navajo Water Management Branch to share what I’ve learned to this point. I developed a fact sheet to help illustrate progress on the research, to help facilitate information sharing, and to guide discussions about how the research is addressing the questions we initially chose to pursue.  Water managers were interested in these preliminary results, particularly the potential to gain a historic record of lake area changes for major surface waters in the Chuskas.

The first half of the 2017 Climate and Society Fellowship has proven to be wonderfully productive and fulfilling. I am looking forward to the next six months of generating results and use-inspired products.


Rainlog Climate Summary – August 2017

Tuesday, September 5, 2017

After an exceptionally wet July for many areas across Arizona, monsoon storm activity slowed down to a crawl leading to unusually dry conditions over the past month. August is typically the wettest month during the summer monsoon season in Arizona and the lack of thunderstorm activity stands out against the frequent and heavy activity that characterized much of the month of July. There were three days in August where no rainfall fell anywhere in Arizona (August 8th, 16th, and 18th), a strange and unusual occurrence in the heart of the monsoon season. The long-lived surge of moisture from the Gulf of California and reasonably favorable position of the upper level high pressure system that supported the frequent thunderstorm activity in July broke down in early August leading to much less favorable conditions for monsoon activity. The upper level high retreated south into Mexico ushering in drying upper level winds from the southwest and suppressing much of the thunderstorm activity across the state. Some higher elevation areas have been able to fire off afternoon thunderstorms on a handful of days in August, but most lower elevation areas have been left out of the action.

The overnight period of August 12th into the morning on the 13th was one of the heavier, widespread rain events that occurred during the month. Tropical Storm Jova passed west of Baja California around this time helping to push a slug of moisture up into southern Arizona. This provided the fuel for an outbreak of heavy thunderstorm activity in the overnight hours on the August 12th. Rainloggers in the Tucson metro area reported widespread amounts in excess of 1” with a handful of reports above 2.5”. Reports of daily totals in excess of 1” extended from southeast Arizona (Bisbee, Douglas, Sierra Vista) up through Phoenix and as far north as Prescott with this event.  

Overall, August precipitation totals look bleak across much of Arizona with respect to average levels. Some isolated areas have received average to above-average August totals, but most of Arizona has observed less than 75% of average with some locations (far northeast and parts of central AZ) seeing less 25% of their typical average total August precipitation. The monsoon season typically winds down through the first couple weeks of September, but the threat of tropical storms and associated moisture will keep the prospect of additional precipitation alive for this season.

Ask an Applied Climatologist - Q&A - How did observed weather correspond to (El Niño) climate predictions?

Tuesday, January 12, 2016

Looking back at Oct-Dec; Did observed weather events correspond with expected (El Niño) climate patterns?

January has kicked off with a bang, and the much anticipated super-mega-Godzilla El Nino is upon us.  El Niño conditions have been in place for months (Figure 1: Oceanic Niño Index), but has this El Niño event been impacting the weather of the Southwest in ways that are expected? Sort of, but not exactly.

This is probably to be expected, as we and others have been saying, no two El Niño events are alike (which means they are hard to compare), AND the October-November-December time period is still very early season for El Niño in the Southwest, so it would be premature to judge it too harshly, or to call this as having gone off the rails.

First off, the October through December time frame is a period of transition for the Southwest where we move from our summer monsoon thunderstorm season into a more westerly upper level circulation pattern and look expectantly for winter storms to bring precipitation to the region. October is also the time where a tropical storm can either directly or indirectly bring a boatload of moisture that can bring heavy precipitation to the region. Even during a ‘normal’ year with no El Niño influence, it is a ‘noisy’ time with lots of moving parts and potential variability, with quite a few dry and wet extremes in the historical record.  Long story short, El Niño or not, we expect to see a lot of variability during this transition season, so the larger question is how much does El Niño typically impact this season?

The influence of El Nino during this Oct-Dec transition operates through the mechanisms of tropical storm activity and early winter storm tracks, both of which can impact precipitation patterns across the Southwest. Typically, tropical storm activity is enhanced in the east Pacific during strong El Niño events, raising the likelihood of above-average precipitation from these events.  And the southward shift in the winter storm track, which is a hallmark impact of El Niño events, can set up as early as November. Based on this, we did largely expect this period to be wetter than average for Arizona and New Mexico and it mostly was (Figure 2: Departure from Normal Precip Oct-Dec 2015). But when we look a bit more closely, how we got this precipitation was a bit unusual, and it really didn’t fit the typical El Niño driven patterns.

For example, in October a series of cut off low pressure systems wandered across the Southwest (at one point, the same cut off low visited Arizona twice) picking up abundant tropical moisture to the south and creating widespread precipitation events across Arizona and New Mexico. These cut-off lows formed off a very busy jet stream pattern across the Pacific Ocean that in part was energized by all of the tropical storm activity across the basin (see the NOAA discussion here). Instead of directly interacting with tropical storms in the east Pacific, El Niño appears to have brought us to above-average precipitation for October in a much more complicated way (Figure 3: Departure from Normal Precip Oct 2015).

A highly amplified jet stream pattern continued into November, again partially driven by tropical storm activity being absorbed into the jet stream in the west Pacific (see NOAA synoptic discussion), leaving the Southwest to contend with a busy weather pattern but very little to work with in the way of moisture. A parade of storms marched through the Southwest through the month, but originated in the Gulf of Alaska and brought very little moisture with them. Some higher elevation and more northern areas were able to squeak out some precipitation with these storm systems, but overall the month was cool and relatively dry for the Southwest (Figure 4: Departure from Normal Precipitation Nov 2015). This was in contrast to the expectation of a much stronger subtropical jet (which was present, but south of AZ and NM) pulling in abundant moisture from lower latitudes.

December was largely characterized the by same pattern with the Southwest seeing passing storms and cooler than average temperatures, but little in the way of precipitation (Figure 5: Departure from Normal Precipitation Dec 2015). New Mexico was able to buck this trend a bit late in the month as a historic blizzard (compared to a similar snowstorm that hit the region in January of 1983, also a strong El Niño winter) swept through the area. 

The final precipitation totals for Oct-Dec 2015 across the Southwest are more or less what you would expect (generally above-average precipitation across New Mexico and northern AZ) for an El Niño year and a bit of the unexpected (drier-than average conditions across parts of western Arizona). But again, maybe that is what we should expect. Two other strong El Niño events (1983, 1997) are depicted for the same time period and are very different from each other. Oct-Dec 2015 establishes itself as yet another flavor of potential precipitation impacts during the fall season across the Southwest U.S.

Notes from an Applied Climatologist: How does El Niño affect the monsoon in the Southwest?

Sunday, October 18, 2015

Research on the interactions between El Niño events and the North American Monsoon System suggests that during past El Niño events, there was a slowing of the onset of monsoon precipitation across the Southwest U.S.  

In summer 2014 the monsoon moved in right on time, ushered in by surges of moisture that moved up the Gulf of California into the desert Southwest, several of which were triggered by tropical storms and hurricanes in the eastern Pacific that flourished in highly favorable conditions, including light upper level winds and very warm ocean water.  These conditions were not necessarily related to El Niño, as conditions that favor an El Niño event were largely absent in the atmosphere, with only glimmers of favorable patterns of sea surface temperatures across the eastern Pacific Ocean, and the fact that the current El Niño had been struggling to form (in 2014) may be one reason we had a relatively "normal" start to the monsoon (in 2014)

In summer 2015, monsoon moisture moved in ahead of schedule in late June with dewpoints in southern Arizona skyrocketing from the low 30’s (F) in mid-June to above 60F by the end of the month. Abundant tropical moisture was drawn north up into the Southwest as the subtropical ridge expanded and strengthened over the western U.S. Previous research on connections between monsoon onset and El Nino suggest that during strong El Nino events, the subtropical ridge struggles to form early on and delays the onset of the season. This was not the case this year as a moderate to strong El Nino was fully engaged with the atmospheric circulation pattern across the globe. It is possible that strong Madden-Julian Oscillation activity through June helped offset some of the typical ENSO effects on the North American Monsoon early on in the season.

For more on this year's monsoon, see the monsoon recap in the Oct 2015 CLIMAS SW Climate Outlook

Notes from an Applied Climatologist: East/West Cold/Hot Dichotomy Q&A

Friday, February 20, 2015

Originally published in Feb 2015 CLIMAS Southwest Climate Outlook:

Why has it been so cold on the East Coast, and so warm in the Southwest?  Where does this fit into climatic patterns?  And is this extraordinary or just variability?

The weather pattern across the U.S. has been pretty extreme over the past weeks, with record cold and snow across the East and record to near-record warmth in the West. Why is the country so divided? In short, a wavy jet stream is to blame (Fig. 1). This high-altitude stream of fast-moving winds has been carving a circuitous path around the globe for much of the winter. The path of the winter mid-latitude jet stream around the globe (in both hemispheres) can give a good indication of where storms are tracking and where warm and cold spots at the surface are emerging. If the jet stream gets stuck in any position, then places getting storms can continue to see a parade of storms, while warm and dry places stay warm and dry. 

Image Source - NOAA-Earth Systems Resarch Laboratory (ESRL)

This winter, the mid-latitude jet stream in the Northern Hemisphere has been very wavy, or meridional [1], with ridges—large-scale bulges—to the north and troughs to the south. Ridges are associated with warm and dry conditions, while troughs are associated with cold and possibly snowy or rainy conditions. Over the past several weeks, this warm West/cold East pattern has dominated, with a persistent ridge of high pressure across the West and a very cold trough across the East (Fig. 2).  Last year, similar conditions drove California and much of the Southwest deeper into drought and unleashed record-setting cold [2] in the eastern U.S. This year, these conditions have broken down on occasion, allowing for storms to bring some precipitation to the West and for the East to warm up for brief periods.

Researchers are trying to determine why this dichotomous pattern has emerged and persisted over the past couple of years. Some climate scientists propose that a warming Artic and declining sea ice [3] are contributing to an increasing frequency of wavy and stuck jet stream events. Other scientists argue that warming water [4] in the tropics and shifts in tropical convection are at play in impacting the winter jet stream pattern. This winter appears to be a complex interaction of many different factors [5] and will be studied in more detail over the coming year to see how it fits into these active areas of research.

Image Source - NOAA-ESRL &

Additional Resources

  1. Meridional: In meteorology, a flow, average, or functional variation taken in a direction that is parallel to a line of longitude; along a meridian; northerly or southerly; as opposed to zonal. 
  2. U.S. temperature extremes and the polar jet stream
  3. Evidence for a wavier jet stream in response to rapid Arctic warming
  4. Record-breaking winters and global climate change
  5. Synoptic Discussion - January 2015

Notes from an Applied Climatologist: Dec 2014 Rainlog Climate Summary

Monday, January 5, 2015

After a very dry and warm November, the weather pattern turned more wintry and active in December bringing some much needed precipitation to Arizona. The first major weather event of the month occurred in the first couple of days as a weak low pressure system interacting with plentiful subtropical moisture brought widespread precipitation to much of Arizona on the 2nd through the 4th of December. This was a relatively warm storm with very high snow levels. Rainloggers from Prescott to Flagstaff reported total rainfall (very few reports of snow) of 1 to 2 inches with this storm system. Much lighter precipitation amounts were recorded by Rainloggers in far southeastern Arizona with amounts of less 0.2 inches.

A much colder storm system pushed through the state towards the middle of the month with lower snow levels and more accumulating snow to higher elevation areas. Precipitation amounts were much lighter with this system, though, with Rainloggers from Tucson to Phoenix to Prescott reporting total precipitation amounts of 0.25 to 0.5 inches over the period of December 12th to the 14th. Some higher amounts close to an inch were reported near Sedona and Show Low with much lower amounts (less than 0.2” inches) observed across far southeast Arizona.

The active weather pattern continued for the rest of the month with quick moving storm systems hitting the state on the 17th and again on Christmas day with light precipitation and snow to higher elevation areas. The month and year ended with a very cold and wet storm system moving through Arizona on New Year’s Eve bringing snow to low desert areas and several feet of snow to mountain locations.

Even with the active weather pattern, only parts of central and southern Arizona near Tucson observed average to above-average precipitation for the month. Much of the rest of the state didn’t keep pace and observed below-average precipitation for December. The latest update of the U.S. Drought Monitor shows that all of Arizona continues to observe short-term drought conditions with little change over the past several weeks.

Overall, 2014 was a strange year of extremes with much of Arizona observing a very dry winter last year and very active summer monsoon season. This left much of southern Arizona with near average precipitation due to the heavy summer precipitation canceling out the dry conditions of last winter. Far northern Arizona still observed below-average precipitation for the year due to both dry winter and summer conditions. All of Arizona observed much above average temperatures for the year with many locations observing their warmest year on record. The Tucson National Weather Service reports that 2014 was the warmest year on record for Tucson with observations going back to 1895.

Notes from an Applied Climatologist - Nov 2014 Rainlog Climate Summary

Monday, December 1, 2014

A pesky ridge of high pressure over the east Pacific dominated the weather for much of November.  This steered storms well to our north and east, leaving Arizona with unusually warm and dry conditions.

The month started off with promise, as a strong and relatively cold low pressure system dropped down the West Coast, clipping northern Arizona as the storm turned east. This system was largely starved of moisture, but managed to bring some light precipitation (and even some snow) to parts of northern Arizona. Rainloggers in Flagstaff reported precipitation amounts of 0.1 to 0.5” inches on the 1st and 2nd of the month. Other parts of the state, including the area along the Mogollon Rim near Show Low and down into southeast Arizona, saw limited precipitation over the next several days as the low pressure system became a closed low and wandered to the south and into Mexico.

This bit of weather and moisture was short lived. A strong ridge of high pressure quickly built over the east Pacific and desert Southwest causing temperatures to rise well above average and the persistence of a dry weather pattern through the middle of the month. Strong storm systems entering through the Pacific Northwest started to weaken and flatten the ridge towards the middle of the month causing temperatures to moderate to near-average levels across Arizona, but brought very little in the way of precipitation. Northeast Arizona was clipped by a weak system on the 15th and 16th that brought very light precipitation to mostly high elevation areas along the Mogollon Rim. A handful of Rainloggers in the Show Low and Springerville areas reported precipitation amounts of 0.1 to 0.3 inches over this period.

The end of November was again at the mercy of the strong east Pacific ridge as it built quickly again over the last week of the month. Temperatures were at record or near-record levels across the state on the Thanksgiving holiday. The Tucson National Weather Service reported that the high temperature of 83F was the 6th warmest Thanksgiving on record for Tucson.

All of the state observed below-average precipitation with much of the west and central parts of Arizona observing no precipitation at all, and short-term drought conditions remain firmly entrenched across all of the state. El Nino still appears to be on its way and may still bring some relief in the form of average to above-average precipitation over the next several months.


Notes from an Applied Climatologist - Oct 2014 Rainlog Climate Summary

Friday, November 7, 2014

Very warm conditions and a couple of unusually wet days characterized the weather of October across Arizona. The month started off rather quiet as an exiting cold front left relatively cool and dry conditions in its wake over the first couple of days of October. A strong ridge of high pressure was able to nose its way back into the Southwest during the first week of the month rapidly pushing temperatures back up to near-record levels across Arizona with temperatures well into the upper 90’s across the low deserts. This rapid warmup was followed by a rapid cool down with an impressive rain event that unfolded across southern Arizona on October 8th and 9th. The busy eastern Pacific tropical storm season wasn’t done with Arizona yet with tropical storm Simon helping to guide abundant moisture into the region just in time for it to interact with a weak trough of low pressure swinging in from the west. This produced several rounds of heavy rain primarily across southern Arizona with many Rainloggers in the Tucson area reporting 1-2” of total precipitation. Rainlogger north and east of Phoenix and across southeast Arizona also reported decent rainfall totals of 0.5 to 1.5” inches with this tropical event.

The weak trough moving through the region kept temperatures in check for a few days before the ridge was back with the heat. This lasted until a weak low pressure system wandered in from the Pacific towards Arizona on the 18th and 20th of the month helping to fire off isolated thunderstorm across primarily central and southern parts of the state. Rainlog reports of precipitation were spotty with this event with some isolated reports of over 1” near Phoenix and south of Tucson with many obervers from Sierra Vista to Globe to Show Low reporting 0.3 to 0.5” inches with these storms.

The month rounded out with more near-record warmth and overall dry conditions. Precipitation totals for the month were generally above average across southern Arizona which saw the bulk of the storm activity and below-average across the northern half of the state which observed very little to no rainfall for the month. The Tucson National Weather Service Office reports that October of 2014 was the 3rd warmest on record and the record when considering only low temperatures. Across the state temperatures were generally 2-6 deg F above-average. Even with the unusually wet conditions across the southern part of the state, longer-term drought conditions persist across all of Arizona. Our eyes now turn towards the winter with the continued hope of an emerging El Nino bringing hopefully average to above-average precipitation for the Southwest.

Notes From the Field: Preparing for Climate Change Along the US-Mexico Border

Monday, October 27, 2014


On September 10-11, 25 scientists and natural resource managers met at the offices of the International Boundary and Water Commission (IBWC), in El Paso, Texas.  Their goal was to use strategic scenario planning techniques to gain insight into environmental and natural resource planning under highly uncertain conditions. Participants included climatologists, meteorologists, geologists, hydrologists, ecologists, biologists, and environmental economists, representing a range of U.S. and Mexican federal agencies, state agencies, universities, and non-governmental organizations.

The workshop was organized by an ad hoc consortium of partners that consisted of:

The workshop focused on riparian zones and adjacent ecosystems in the Big Bend reach of the river, including the Rio Grande Wild and Scenic River, and the Monumento Natural Río Bravo del Norte en Mexico. During the two-day workshop, participants were briefed on the climate, hydrology, and ecology of the region.

Workshop Goals

  • Introduce participants to scenario planning methods for dealing with situations of high uncertainty—especially with respect to climate—and making use of climate information in decision making
  • Foster a spirit of collaboration and build bilateral teams for ongoing planning,
  • Exchange knowledge with regional risk managers about decision making needs, climate forecasts and projections, decision contexts, constraints, and risk tolerance,
  • Increase awareness of regional efforts, in order to identify areas of mutual interest and facilitate coordination and collaboration.

Dr. Holly Hartmann (Holly C. Hartmann Consulting)introduced workshop participants to strategic scenario planning techniques used by industry, the military, and some federal agencies, and facilitated most of the scenario planning exercises [2].  These techniques are focused on addressing factors outside the control of resource managers, such as climate or economic fluctuations, and were designed to help managers make informed decisisons despite considerable uncertainty.

NOAA scientists from the National Climatic Data Center, NOAA’s Southern Region office, and the El Paso Weather Forecast Office, worked with regional and state climatologists, including CLIMAS’s Dave Dubois (New Mexico State University), to assess plausible future conditions despite highly variable climate factors, including summer precipitation totals and the date of onset for the North American Monsoon (NAM). Texas State Climatologist, John Nielsen-Gammon (also an affiliate of the SCIPP RISA), laid out key facts about the regional climate:

  • The region receives the vast majority of its annual precipitation during the summer season,
  • Regional precipitation variability is exceptionally high, and
  • Aside from temperature-related soil moisture decreases, there is very high uncertainty associated with climate model projections of future precipitation.

During wide-ranging discussions about the uncertainty of future climate conditions, we considered possible eastward and westward shifts in the center of action of the NAM in the border region, the timing, intensity, and amount of summer precipitation, the severity and extent of regional drought, and the impact that these factors might have on river hydrology, especially sediment flows [3].

What We Accomplished

Participants developed four preliminary scenarios focusing on:

  • Uncertainty regarding the amount and timing of future precipitation;
  • How future cooperation between stakeholders amplifies or moderates future environmental challenges; and
  • The degree to which implementation of management actions is based on correct scientific understanding of future environmental changes.

Discussion amongst participants revealed a need for more cross-border collaboration to increase preparedness and coordination, and to achieve positive outcomes in the face of future climate conditions such as sustained drought or increased flash flood frequency.

Toward the end of the workshop, IBWC Commissioner Edward Drusina, took time from his busy schedule to address the participants. He emphasized the need to build capacity, on both sides of the international border, for timely and informed responses to the challenge of drought and extreme climate variations. He urged participants to make it a priority to communicate their knowledge to society.

Key outcomes of the workshop:

  • Increased capacity in the Rio Grande-Río Bravo bi-national region for using scenario planning to address uncertainty in future climatic conditions;
  • Preliminary climate change scenarios for the region, including plausible scenarios of future environmental and social impacts; and
  • Enthusiasm for continued and more detailed and deliberate bi-national discussions of these issues.

Next steps in this process:

  • Expand scenario planning methods to a broader stakeholder group interested in the region, and
  • Continue the scenario planning process by exploring existing and alternative scenarios in greater depth, and developing a portfolio of potential adaptation actions and strategies.

These steps will engage additional participants using workshops in Mexico and the U.S.

The Desert LCC is also looking to apply the climate scenario methodology presented at this workshop to landscape conservation planning and design.

Acknowledgment: This blog post benefited greatly from input by the workshop organizing committee, mentioned above


  1. About the North American Climate Services Partnership (NACSP) - In 2012, the weather services of Canada, the United States (NOAA), and Mexico signed a statement of intent to facilitate the exchange of information, technology and management practices related to the development and delivery of climate and water information for North America. The goals of NACSP are similar to those of CLIMAS: to foster the development of partnerships with the users of climate information, to enhance and improve the use of climate information by decision makers, and to create opportunities to share lessons learned from pilot projects and research. In 2013, yours truly was designated the co-chair of the Rio Grande/Rio Bravo pilot project. More information about the NACSP.
  2. Hartmann's ongoing work on scenario planning and decision support has been pivotal for land management agencies such as the National Park Service and the Bureau of Land Management.
  3. During the last 50 or more years, sediments have been accumulating in the Big Bend reach of the Rio Grande; this has caused a degradation of habitat for fish species and other animals and plants.

Image Credit:

  1. Figure 1: US/Mexico Region - Source: Mark Briggs - World Wildlife Fund
  2. Figure 2: Big Bend National Park & Rio Grande Wild and Scenic River - Source: Billie Brauch vs. Jeffery Bennett - National Park Service - US Dept of the Interior.

Notes from an Applied Climatologist - Sept 2014 Rainlog Climate Summary

Friday, October 3, 2014

September turned out to be quite a month as far as extreme monsoon season weather across Arizona. The month started out rather quiet as the monsoon ridge of high pressure weakened and a trough of low pressure to the north ushered in dry air from the west across the state. This suppressed thunderstorm activity for several days until the monsoon ridge pushed back north helping to bring low level moisture back into the region. At the same time Hurricane Norbert was moving along the west coast of Mexico towards the southern end of the Gulf of California. By September 7th, Norbert helped spark a deep surge of moisture up the Gulf of California into the low deserts of Arizona. This sopping wet atmosphere turned into several rounds of heavy rain across both the Phoenix and Tucson metro areas breaking several daily precipitation records for these areas. Many Rainloggers in Mesa, Tempe and Chandler near Phoenix reported totals ranging from 4 to over 6 inches with this rain event. Tucson Rainloggers also reported 2 to 4 inches of total precipitation with this event. Widespread flash flooding crippled both of the metro areas and near flood flows were observed on several of the main water courses in the Tucson area.

If that weren’t enough excitement for the month, a second hurricane impacted the region although directly this time later in the month. Hurricane Odile took a similar path to Norbert early on, but turned more northerly striking the southern tip of the Gulf of California on September 15th and traveling north along the spine of Baja California creating wide swaths of wind and flooding damage in its wake. Odile’s path north helped usher in additional moisture to the low deserts of Arizona which raised the risk of flash flooding across the region. Of even more concern was the prospect of the circulation remnants passing right over southern Arizona which raised the risk even further of widespread flooding rains. Ultimately, the remnants of Odile tracked further south than expected bringing most of the flooding rains to northern Mexico where precipitation reports in excess of 7” were common. Far southeast Arizona in Cochise County was not spared by Odile, though. Many Rainloggers from Sierra Vista to Douglas to Portal reported precipitation totals from 3 to over 5 inches with this event. Flash flooding sparked by Odile in the Chiricahua Mountains ripped through the small town of Portal and destroyed a Forest Service road critical for the region.

A cold front on the 27th was the close out event for the 2014 monsoon season, which sparked several rounds of severe thunderstorms across the state with damaging winds and flash flooding reported in central and northern parts of the state. Rainloggers in Prescott reported 1 to almost 3 inches with these thunderstorms as they moved through the region.

Overall September was unusually wet over the low deserts and near to even below average across higher elevations and across much of the plateau of northeastern Arizona. The monsoon season as a whole officially ended on September 30th with much the same pattern across the state with the much of western and central Arizona observing above-average precipitation and the northeast corner of the state observing less activity and below-average precipitation. Short-term drought conditions improved in some of these areas that received above-average precipitation, but longer-term drought conditions persist across the region.

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Notes from an Applied Climatologist: Monsoon End Q&A

Monday, September 29, 2014

How Do We Know When the Monsoon is Over?

Across the southwest United States, the start of the summer monsoon season is pretty easy to recognize once you have experienced it firsthand a few times. Typically, one week it's hot and dry, and the next week, it's hot and sticky, but hopefully raining. This is a predictable part of the southwestern summer, and typically happens in late June or early July across Arizona and New Mexico (often first in New Mexico with Arizona trailing just behind). The start is relatively clear cut, but calling an end to the monsoon season is a bit trickier, because there isn’t a rapid and clean transition back to some other non-monsoon weather conditions in the fall, and the presence of monsoon breaks can complicate this transition.

The monsoon circulation pattern and resultant precipitation across the Southwest is largely governed by the position and strength of the subtropical high, also known as the monsoon ridge. This high pressure system builds north through Mexico into the Southwest from June into July, causing the winds to shift from a dry westerly flow in mid-levels of the atmosphere to a moister, subtropical easterly flow. This shift in wind direction is a key to defining the beginning, as well as the end of the monsoon season. The monsoon ridge typically starts to weaken and retreat through the month of September, but can build and subside throughout the month. September is also often a time when tropical storm moisture can interact with early season autumn storms moving in from the north Pacific, sparking widespread thunderstorm activity. These ‘transition events’ are further indication that the monsoon season is almost over and that fall weather is on the doorstep.

Notes from an Applied Climatologist: Precipitable Water Q&A

Friday, September 12, 2014


What are the different ways that moisture is tracked in the SW?

Measuring accumulated precipitation is a (relatively) straight forward process that mostly involves a ground-based network of rain gauges that measure the depth of rainfall that accumulates, although some gauges, like tipping bucket gauges, also measure intensity. 

Tracking the atmospheric moisture that sets the stage for precipitation events is a much more complicated endeavor. Atmospheric moisture varies at all levels in the troposphere - the lowest level of the Earth’s atmosphere and where our weather happens.  This requires a three dimensional approach (really four dimensional when you factor in these measurements are made over time) when measuring and tracking atmospheric moisture.

The primary way that the vertical dimension of the atmosphere is sampled is with weather balloons and radiosondes. These are instrument packages attached to helium balloons that measure atmospheric pressure, temperature and humidity, as they quickly ascend (about 1000 ft/minute) through the tropopause. This is done twice a day at approximately 1000 locations across the globe. The data collected through each radiosonde launch creates an atmospheric profile of the wind, temperature and humidity patterns above that location. This atmospheric profile is fed into global weather models and is a critical data component of accurate forecasting.

With respect to atmospheric moisture, the vertical profile gives an indication of where and how much moisture is available for supporting the development of precipitation. High amounts of low level moisture near the surface can be an important source of fuel in the development of unstable air and convective thunderstorms. High amounts of mid-level moisture can sometimes support high-based thunderstorms where the rain that falls evaporates while falling into drier lower levels, producing strong outflows and gusty winds at the surface. When moisture is present at all levels in the atmosphere, these conditions can support widespread, heavy rainfall events.


Precipitable Water

One way of quantifying the total amount of moisture in a vertical atmospheric profile is through the calculation of a metric called precipitable water. This is the amount of water (often in a depth of inches or millimeters) that could be condensed out of a vertical column of air extending up through the troposphere. This value is calculated with the data from each radiosonde sounding twice a day and is also estimated through satellite data as well (see image above).

Precipitable water values are carefully monitored across the southwest U.S. throughout the monsoon season, because they help diagnose the amount moisture available to fuel convective thunderstorms and heavy rain events. Values through the monsoon season can vary widely across the Southwest, but daily values are typically between 1 and 1.5 inches in Tucson as an example. Higher elevation areas have less atmosphere to work with, so precipitable water values will naturally be lower.

To put these values in context, the precipitable water value at Tucson collected from the morning radiosonde on September 8th, the day that widespread flooding occurred across Phoenix and Tucson, was an even 2 inches. This was a record high value for September at the Tucson site. This value of 2 inches of precipitable water actually turned into much higher local precipitation amounts. This is because converging air can cause precipitable water values to pile up and feed individual storms, leading to much higher local precipitation amounts than would be achieved if simply squeezing the water out of a single column of air.

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Figure 1: NOAA Weather Balloon - Source: NOAA
Figure 2: Precipitable Water in the Last 72 hours (as of 09.15.2014) - Source: Cooperative Institute for Meteorological Satellite Studies
Figure 3: Precipitable Water Jan-Dec, Tucson AZ - Source: NOAA

Notes from an Applied Climatologist - Aug 2014 Rainlog Climate Summary

Monday, September 8, 2014

The monsoon season continued to roll along throughout August, bringing abundant precipitation to much of Arizona, yet some places were still between the rain drops, as is typical with summer thunderstorms in the southwest. The month started off strong, with the monsoon ridge pushing to the north over the first couple of days of the month.  This helped to usher in low-level moisture, and fueling scattered thunderstorms across the state.

This didn’t last long, and by end end of the first week of August, a low pressure trough off the coast of California weakened the ridge and shifted it to the east. This pushed the low-level moisture south, and caused a brief dry out across much of Arizona. During this mini-break, we saw limited thunderstorm activity in the higher elevation areas of the southeast corner of Arizona between Aug 5th and Aug 10th.

Beginning on the 11th, the monsoon ridge pushed north again, helping to restart the deep southerly flow of moisture into the Southwest.  August 12th was a (very) big day for rainfall, as organized thunderstorms brought several rounds of heavy precipitation from southeast Arizona all the way up to Flagstaff.  Parts of Yavapai County observed over 5 inches of rain on the 12th with many Rainloggers from northern Phoenix to Prescott and Flagstaff reporting 2 to 3 inches of total rainfall.

This deep moisture remained in place over the next 10 days, which helped fire off afternoon thunderstorms each day in higher elevation locations, and with the occasional storm wandering into lower elevation valley areas.  Rainloggers in Yavapai County noted another busy couple of days from August 17th to the 19th, with daily rainfall totals between 0.5 to 1.5”, and with multiple day totals of close to 3 inches.

The second major dry-out occurred the last week of the month as a very Autumn-like low pressure system moved across the western U.S., which knocked the monsoon ridge back south. August wrapped up with several days that were completely devoid of observed precipitation anywhere in Arizona.

For the month overall, most of the state observed average to above-average precipitation, with the driest spots being in Pinal County and far northern Apache County. Short-term drought conditions improved across much of the state with the rainfall, but long-term deficits still remain and will take several more above-average seasons to catch up. 

Notes from an Applied Climatologist: Tropical Storms and the Southwest Q&A

Tuesday, August 26, 2014


How do (Pacific) tropical storms affect the weather patterns of the SW?  What type of tropical storm paths affect weather in the SW? 

Figure 1: Tropical Storm Formation by Date - Source: NOAAFigure 2: Pacific Moisture Flow into Southwest - Source: NOAAThe eastern Pacific Ocean along the west coast of Mexico and central America are an active area of tropical storm formation through the summer and early fall (typically between June and September) (Figure 1). Warm water and light winds create the perfect conditions in this region for thunderstorms to flare up, and eventually organize into tropical storms and hurricanes.

Surprisingly, the landlocked southwest U.S. is impacted by these storms in a variety of ways. The most common way is by inducing surges of moisture up the Gulf of California into Arizona that can fuel widespread outbreaks of monsoon season thunderstorms.

Clusters of storms or tropical systems that pass near the mouth of the Gulf of California can produce a cool outflow of winds and create a pressure differential up the Gulf of California (high pressure near the cool thunderstorm outflows and low pressure near the hot conditions and rising air typical in the lower Colorado River valley at the north end of the Gulf). This pressure differential leads to the surge of moisture traveling from south to north, up into the low deserts of Arizona, and sometimes southern California (Figure 2).

Tropical storms and hurricanes in the eastern Pacific can sometimes actually impact the Southwest through a direct hit (Figure 3). Easterly winds will typically carry eastern Pacific storms west out to sea, but storms that take a more northwesterly track along the Mexican coast can eventually track north or even northeast. This typically happens later in summer or in early fall, as the subtropical high pressure system retreats south giving way to very light winds aloft in no particular direction or stronger westerly winds advancing from the north, the sign of fall and winter approaching. When tropical storms move north and aren’t steered away from the coast of Mexico they can continue to wander north or can get caught up in westerly flow aloft and directed inland towards southern California and Arizona.

Figure 3: Historical Tropical Storm Tracks in the SW, Figure 4: Hurricane Octave Flooding 1983 - Source: NOAA

Hurricanes weaken quickly when they encounter land and break away from their energy source of warm ocean water, so only weak tropical storms or ‘remnant low’ pressure systems actually make it to inland locations like Arizona. Still, these systems are often potent rain producers bringing with them abundant moisture and a source of lift to produce widespread thunderstorms and can produce very dangerous and widespread flash flooding events. The infamous flash flooding disaster that occurred in October of 1983 was caused by tropical storm Octave where much of Arizona observed record precipitation and catastrophic flooding (Figure 4).

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Figure 1: Tropical Storm Formation by Date - Source: NOAA
Figure 2: Pacific Moisture Flow into Southwest - Source: NOAA
Figure 3: Figure 3: Historical Tropical Storm Tracks in the SW - Source NOAA
Figure 4: 1983 - Hurricane Octave and Flooding in the SW - Source NOAA

Notes from an Applied Climatologist: Q & A on El Niño, Predictions, and Indices

Wednesday, August 13, 2014


What is the criteria to call something El Niño?  Is El Niño a continuum or is there a binary switch where it's either an El Niño event or not?

There are actually several different indices or metrics used to track the state of ENSO (the El Niño-Southern Oscillation) across the Pacific Ocean and whether oceanic and atmospheric patterns reflect El Niño, La Niña or neutral conditions. Some of these indices look just at the atmosphere (for example Southern Oscillation Index), some just at the ocean (for example Niño3.4 index) and some the combination of both (for example the Multivariate ENSO Index). All have different strengths and weaknesses, but oceanic based indices tend to reflect the more slowly evolving part of ENSO, the shift in sea surface temperature patterns, which in turn can have an impact on global weather patterns over many months or seasons.

The NOAA Climate Prediction Center uses the Oceanic Nino Index (ONI) which is the running 3-month average of sea surface temperature anomalies (or departures from average) across a key part of the central equatorial Pacific from just west of the International Date Line back towards the east to 120W longitude.

Tracking sea temperatures in this region provides a good indication of whether or not tropical convection (which is driven by warm waters) is shifting or may soon shift unusually far east along the equator during El Nino conditions or far west during La Nina events. ONI values typically range from -2.5 which would be indicative of a strong La Nina to 2.5 which would be a strong El Nino event. The NOAA-CPC makes a distinction between the emergence of El Nino or La Nina conditions which would be ONI values climbing past the +0.5 (El Nino) or -0.5 threshold at the monthly scale as well as other atmospheric indications like shifts in wind and rainfall patterns versus a full blown event that lasts for many months or over seasons. An event requires ONI values to be greater than the +0.5 or -0.5 threshold for at least five consecutive months (more details at


How closely linked is the strength of El Niño with observable effects in the Southwest?  Would a weak El Niño look that different from no El Niño at all?  

The strength of an El Nino event does seem to matter with respect to seasonal climate connections here in the Southwest. Looking at past precipitation patterns during El Nino winters of varying strengths, you notice that strong events (ones with ONI values >1.5) tend to have a more reliably wet look to them versus weak events which vary from above-average to even below-average.

The forecast of a strong El Nino event tends to lead to a subsequently more confident outlook in wet conditions for Arizona and New Mexico. If the event is forecasted to be weak or even moderate the outlook for precipitation over the upcoming winter season is much less certain (more on this topic

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Notes from an Applied Climatologist: El Niño & Drought Q&A

Wednesday, August 6, 2014


There’s been a lot of talk about El Niño and ‘busting the drought'.  How much can El Niño help with ongoing drought conditions in the West?

The El Niño event struggling to form in the Pacific Ocean has been a ray of hope for many of us across the Southwest for several months now looking for some relief from both short and long-term drought conditions that have plagued California, Arizona and New Mexico for several years now. The important thing to remember is that we can only expect *some* relief in a best case scenario with a strong El Niño event delivering abundant precipitation across the Southwest over the winter season. Current drought conditions have accumulated over years and cannot be erased by a single wet season. We can look back at drought indices around the time of the last strong El Niño event over the winter of 1997-1998.

For a detailed look at Standardized Precipitation Index (SPI) in Arizona - Click Here

Wet conditions were observed across Arizona over several months which dramatically improved short-term drought conditions (months to seasons), but longer term drought conditions (seasons to years) were still present and quickly intensified as dry conditions returned the following year. At this point we will need several years of average to above-average precipitation over each season to alleviate long-term drought conditions. An El Niño winter with above-average precipitation would help, but is not a silver bullet at this point.


Significant amounts of rain fall during the monsoon, why doesn’t that solve our drought problems?

Monsoon precipitation is a critical water source to many ecosystems and agricultural activities (e.g. ranching), and is an important determinant of drought status during the summer across the Southwest. If monsoon precipitation is spotty, late in onset, and overall below-average, short-term drought conditions can quickly intensify across Arizona and New Mexico. As far as long-term drought conditions that evolve over multiple seasons or years, a single monsoon season typically has little impact.

Dry conditions during the summer can contribute to long-term drought impacts like stress in trees and reductions in surface water streamflows, but average to wet conditions often don’t contribute much to improvements. Monsoon precipitation typically falls in torrents of heavy rain associated with isolated storms, leaving a patchwork of runoff and wet soil that quickly evaporates back into the atmosphere. Occasionally, large-scale flooding events during the summer can lead to high flows in streams and contributions to reservoirs and subsequent relief from long-term drought impacts, but these events are rare and unpredictable.  

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Notes from an Applied Climatologist - July 2014 Rainlog Climate Summary

Tuesday, August 5, 2014

July started off with a bang with moisture and thunderstorm activity moving into Arizona over the 4th of July weekend. This start date for monsoon thunderstorm activity was very close to the climatological start date of July 3rd, as determined by the old dewpoint definition (three consecutive days with average dewpoints >= 54F) in Tucson. The ‘monsoon ridge’ of high pressure was in an ideal position over the first two weeks of July to guide abundant subtropical moisture into the state, providing fuel for almost daily thunderstorm activity across parts of southeastern Arizona and the high country along the Mogollon Rim. 

Rainloggers in southern Arizona near Sierra Vista observed amazing precipitation totals of 5 to 7 inches over the first two weeks of the month. Most other areas observed 1-3 inches during this period with higher elevation areas near Show Low and Flagstaff seeing closer to 2 to 4 inches. Most of the Phoenix metro area saw more dust than rain during this period with thunderstorm outflows pushing large haboobs or dust storms through the area numerous times.

Monsoon Tracker Plots - Find More Here

The monsoon ridge was knocked out of position several times the second half of the month leading to a slowdown in monsoon thunderstorms across much of the state. Parts of southeastern Arizona still managed to pick up several inches of precipitation in a handful of storm events. Several Rainloggers near Douglas observed almost two inches of rain on the 27th with a series of storms that moved along the international border. The Tucson and Phoenix metro areas observed isolated storms during this period with lucky neighborhoods seeing up to an inch of rain, but most observing less than 0.25”.

Overall, July was a pretty typical start to the monsoon with some areas observing very heavy rain and many places with a handful of light events. Most of the state is near average for monthly total precipitation with the notable exception of far northeast Arizona which has observed very little in the way of thunderstorm activity. Temperatures were above average across much of the state with the National Weather Service in Tucson reporting that it was the 13th warmest July on record. Overnight temperatures were the big story this past month with Tucson and Phoenix observing several new high minimum temperatures records or ties. The National Weather Service reports that it was the 3rd warmest for Tucson and 5th warmest for Phoenix on record with respect to July minimum temperatures.

Monsoon Summary Maps

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Notes from an Applied Climatologist: Monsoon & El Niño Q&A

Thursday, July 31, 2014


Is the strong start to the monsoon related to El Niño?

In short? Probably not. Research on the interactions between El Niño events and the North American Monsoon System actually suggests the opposite, with past El Niño events slowing the onset of monsoon precipitation across the Southwest U.S.  

This year, when compared to records of average dewpoints across Arizona and New Mexico, the monsoon moved in right on time.  It was ushered in by surges of moisture that moved up the Gulf of California into the desert Southwest, several of which were triggered by tropical storms and hurricanes in the eastern Pacific that flourished in highly favorable conditions, including light upper level winds and very warm ocean water.  These conditions are not necessarily related to El Niño, as conditions that favor an El Niño event have largely been absent in the atmosphere, with only glimmers of a favorable pattern in the sea surface temperatures across the eastern Pacific Ocean. The fact that the current El Niño has been struggling to form may also be the reason we had a relatively "normal" start to the monsoon.

More precipitation maps at


What can we expect from the monsoon (in AZ & NM) with El Niño waiting in the wings?

Research on the interactions between El Niño and the North American Monsoon System suggest that the impact of El Niño is largely observed early in the season, primarily in the months of June and July. This means that even with an El Niño (probably) forming later this summer, its direct impact on the monsoon will likely be minimal.

An indirect effect continues to be the very favorable tropical storm and hurricane conditions in the eastern Pacific related in part to the struggling El Niño event. With more tropical storm activity in the eastern Pacific there is an elevated chance that one of these storms will curve back to the east and visit the Southwest, especially later in August and September. Some of the floods of record across Arizona and New Mexico are related to late monsoon season tropical storms curving back through the Southwest.

Michael Crimmins is an Associate Professor and Climate Science Extension Specialist in the Department of Soil, Water and Environmental Science

Notes From the Field: Thinking Outside the Box with Great Basin Natural Resource Managers

Tuesday, July 15, 2014

On June 25-27, 2014, a team of researchers from CLIMAS and the California-Nevada Applications Program (CNAP) convened a workshop at the Desert Research Institute in Reno, NV.  The goal? We wanted to address the complex and uncertain future of Great Basin land management in the Central Great Basin (California and Nevada), and to provide state and federal agency partners with streamlined and purposeful means of incorporating climate change information into land management practice.

In addition to myself, the project team includes:

  • Tamara Wall (CNAP and Desert Research Institute)—a social scientist with a knack for methods and metrics assessing how climate knowledge is communicated, used and applied to environmental hazards
  • Tim Brown (CNAP and Desert Research Institute)—a long-time collaborator with CLIMAS and one of the nation’s leading fire climatologists
  • Holly Hartmann—whose ongoing work on scenario planning and decision support is pivotal for land management agencies such as the National Park Service and the Bureau of Land Management (BLM) and
  • Julie Brugger (CLIMAS)—an anthropologist whose work on climate concerns among rural stakeholders and land managers brings in consideration of the social and cultural factors that influence the use of climate information in decision making.


The Bureau of Land Management (BLM) manages the vast majority of public land in the Great Basin, and they are interested in practical methods for incorporating climate change information into their on-the-ground practices and operational strategies for land management.

The first phase of our project was funded by the BLM, which is interested in using results from its Rapid Ecoregional Assessments (REA) program in climate adaptation planning, and we put together a workshop to introduce two scenario-planning methods:

  1. Adaptation for Conservation Targets, or ACT, and
  2. Strategic Scenario Planning, or SSP.

We wanted to assess the best uses of these methods, and to learn from workshop participants the best ways to combine these methods for effective planning and implementation of adaptation strategies. Attendees of previous workshops gave feedback that zeroed in on two key ways these methods could be used: some were seen as useful for quick and practical action—a key concern for field managers—while others were seen as more useful in thinking holistically about landscape scale ecosystems—which can assist in long term planning. This split perspective is important and continues to inform our plans to better incorporate REA information into adaptation planning.


Our advisory committee suggested that we focus on the sagebrush-steppe ecosystem, and turn to the challenge of managing cheatgrass (Bromus tectorum). Cheatgrass is an invasive species that is viewed as an environmental game changer in the Great Basin, to the point that BLM researcher Mike Pellant calls it “the invader that won the West.

The characteristic red/purple hue of mature cheatgrass is visible across the Great Basin - NV  306 near Beowawe, Nevada - Photo: Wikipedia Commons

Why is cheatgrass such a threat and what does climate change have to do it?  Cheatgrass is drought-tolerant, is a prolific seed producer, and it is successful at outcompeting native vegetation for resources (water).  Not only that, but it thrives in disturbed areas, especially post-fire, but it typically goes dormant and dries out sooner than native plants, meaning it’s presence actually increases the risk of fire.  This means that in the Great Basin, a post-fire landscape can quickly become dominated by cheatgrass, which provides a blanket of dry fuel lying in wait for the next fire.  Once established, it is incredibly difficult to break this cycle.  This threatens the entire sagebrush-steppe ecosystem, beginning with Big Sagebrush (Artemesia tridentata)—the centerpiece of the ecosystem’s web of interactions and ecological dependencies—and ending with all the species dependent on the native sagebrush environment ranging from big game species, such as elk and deer, to regionally important species such as Sage-Grouse (Centrocercus urophasianus) not to mention a whole network of related animals including mammals, reptiles, insects, and birds.


In preparation for the workshop, the advisory committee and the research team developed a conceptual map of the relationships and interactions between cheatgrass and other factors, such as soil moisture, native vegetation, fire, erosion, grazing practices, energy development, road building and, of course, observed climate variation and projected climate change.

On the first day of the workshop, we used this map to explore the direct and indirect linkages between climate and cheatgrass, and identified points in the system where management could implement strategies in the next decade, to affect the spread of cheatgrass over the next 50 years. This method of addressing future changes is called Adaptation for Conservation Targets, or “ACT” (Cross et al. 2013), and it is used by conservation groups and their partners to quickly develop on-the-ground climate adaptation actions. Through ACT, we focused on aspects of environmental management that managers can actually control.  This is not unlike riding on roller skates through an obstacle course.  You adapt to the obstacles, but you remain connected to the ground.

Holly Hartmann and Tamara Wall Listening to Feedback from Participants.  Photo: Gregg Garfin

On the second day of the workshop, Holly Hartmann introduced Strategic Scenario Planning, or “SSP” (Weeks et al. 2011), which is a method that focuses on factors outside of resource managers’ control, such as regional population growth, laws, the economy, public policy, and climate variability and change. Holly used SSP to help workshop participants develop new ways of thinking about an uncertain future, and for dealing with combinations of highly variable factors—such as changes in winter precipitation, which are critical for cheatgrass growth, and future funding resources, which are critical for implementing projects. The SSP method helps people expand thinking beyond day-to-day actions, to consider how factors may change and interact over time.  This is more akin to learning to surf, you are developing your skill and balance – your ability to adapt and respond to unknown changes, but the ‘ground’ beneath you is constantly shifting and unpredictable.

Holly Hartmann discusses SSP method - Gregg Garfin on Overview of Climate Patterns

By the third day of the workshop, the participants—a great group of highly motivated and dedicated land management professionals from Great Basin state, tribal, and federal agencies—were skating and surfing along.  They provided us with great feedback about using our two adaptation planning methods, and the contrast between the two approaches facilitated a lively and engaging discussion that forced people to consider various overlapping perspectives.

Skating and Surfing Along - The Fruitful Results of Engaged Discussion of ACT/SSP Overlap with Participants - Photo: Gregg Garfin

Lessons Learned

For the researchers, it was amazing to see how the ACT process—which focuses on linear chains of logic to connect climate, environmental change, management opportunities, and management strategies—enabled the workshop group to apply logic statements to the mind-expanding SSP process. The combination was far more powerful.  One workshop participant specifically highlighted the future scenario methods as providing a refreshing contrast to “ready, shoot, aim!” approach that is typical in triage management that simply holds on for dear life dealing with the crisis du jour. Another workshop participant singled out the SSP approach, because it didn’t require everyone to agree on what might happen in the future, but that it encouraged participants to embrace complexity and uncertainty while provoking ideas about how to deal constructively with aspects that are outside of managers’ control.

Our research team is reviewing and refining reports describing the lessons learned at the workshop, but we are also preparing for the next phase of our project (funded by the National Oceanic and Atmospheric Administration - NOAA). Our next step is to organize a working group taken from workshop participants, who are quickly becoming experts in using the REA, to develop a framework for integrating the REA into both ACT and SSP processes. A new national-level dataset on BLM lands offers us the opportunity to inform how the REA data can be used in climate change adaptation planning and management implementation.


We have a webinar planned for October 2014 to build out the scenario sets developed in the June workshop.  We plan to hold a second workshop in November to apply the ACT and SSP processes to strategic management planning. This is an ongoing learning process of how to use multiple scenario methods, individually and in concert, and in the near future, we will incorporate the rich array of future climate and ecological projections from the BLM’s REA studies. We are hopeful that many of the attendees from the first workshop will join us in November, and we anticipate an infusion of ideas from new attendees on how we can best start planning for the future in the Great Basin Region. 

The project website contains information about the project and the workshop described in this posting.

Gregg Garfin is Deputy Director for Science Translation & Outreach, Institute of the Environment, and Associate Professor and Associate Extension Specialist in the School of Natural Resources and the Environment, University of Arizona, Tucson, AZ

Tamara Wall is Assistant Research Professor, Division of Atmospheric Sciences, Desert Research Institute, Reno, NV

Notes from an Applied Climatologist - June 2014 Rainlog Climate Summary

Thursday, July 10, 2014

June was a hot and dry month across Arizona with little in the way of precipitation and lots in the way of wind and extreme fire weather. This isn’t all that unusual for June in Arizona, but temperatures were exceptionally warm and passing weather systems brought unwelcome wind which periodically enhanced fire danger to extreme levels. The weather pattern throughout the month was a battle between the strengthening sub-tropical high to our south and late season spring storm pushing through the Southwest from the north. Several of these storms pushed through the western U.S. tightening the pressure gradient across Arizona leading to several days of gusty, hot and dry southwest winds across the region. 

One passing storm system did manage to pull up some soupy tropical air that pushed north through Mexico with the help of hurricane Cristina. The only substantial precipitation recorded by Rainloggers across the state during June occurred on the 13th across the far southeast corner of the state. Several lucky observers in Cochise County recorded precipitation amounts of 0.1 to 0.3 inches on the 13th as isolated thunderstorms moved across the area.
Overall, the month was unusually hot and dry conditions with no improvements in short-term drought conditions observed across the region. The Tucson National Weather Service Office reported that June 2014 was the 3rd hottest on record and the U.S. Drought Monitor still has all of Arizona under moderate to extreme drought. The monsoon is in full swing which should help alleviate some short-term drought impacts and reduce fire danger across the region. An El Nino event is still trying to get its act together across the Pacific Ocean which may also spell above-average precipitation for the Southwest later this fall and winter.

Notes from the Field: Dendrochronology, Wildfire, and Iron Maiden

Tuesday, June 24, 2014

Chuska Mountains, Navajo Nation - Photo by Dan Ferguson

Just how old are the forests in the Chuska Mountains in the northeastern part of the Navajo Nation?  How might those forests fare in a climate that will be warmer and probably drier than anything they've ever experienced? In early June I had the chance to tromp around in the woods with a group of experts working to answer these questions. Our intrepid leader was UA Laboratory of Tree Ring Research PhD student Chris Guiterman who—I now know—is a man with a plan. The plan goes something like this:

Step 1: Build a mutually beneficial partnership with the Navajo Nation Forestry Department. Judging by the warm reception he received from the Navajo foresters when we showed up for a week of fieldwork, I'm going to call this one done. Chris managed to build a great relationship with the foresters over the last year or so without knowing exactly where the money would come from to do the research. During that time he developed a set of research questions that—when the project is done—will help the Navajo Nation manage their forests and also help all of us better understand how individual forests have responded to previous climate conditions. The hope is that through this project Chris and his colleagues will give us some clues about how these forests may deal with what we expect to be tough 21st century conditions.

Step 2: Find resources to carry out the research. Here's where CLIMAS enters the picture. Chris is one of four outstanding UA graduate students to receive support through our new Climate and Society Fellows program. As it happens, we're not the only group who thinks Chris is on to something good. He recently learned that he'll also be a recipient of a prestigious EPA Star Fellowship to carry out this research. And last but not least, he's attracted the attention of one other funder who may pony up enough money to allow Chris to put together his dream team of UA researchers and Navajo foresters.

Step 3: Do science. I showed up for the very first part of this step, which began the week of June 9. I'm no dendrochronologist, but it was thoroughly enjoyable playing one for a week. Except the 50mph winds. And the dust. And the damned caterpillars falling out of aspen trees. Otherwise, a total blast. Uh, except that increment borer that I broke…oops, sorry Chris.

Photo 1: Chis Guiterman.  Photo 2: Timothy Jim, Chris Guiterman & Herman Yazzie - Chuska Mountains, Navajo Nation - Photos by Dan Ferguson

I learned more in one week about dendrochronology, forestry (and foresters), and the Chuskas than I could have in months of sitting in my office reading. I learned that hitting the pith (i.e., the center) of a tree with a 5mm borer is much harder than it looks. And that an Iron Maiden t-shirt is an excellent uniform for forestry. Mostly, though, I realized that scientists like Chris and his colleagues both at UA and in the Navajo Department of Forestry are doing work that's critical as we try to adapt to an unpredictable climate.

Photo 1: Timothy Jim - Photo 2: Dan Ferguson & Cathy Covington - Photo (1) by Chris Guiterman, Photo (2-3) by Dan Ferguson

The forests across the Southwest—including in the Chuskas—are vital to our region. They play a starring role in our region's surface hydrology. They provide myriad social and economic benefits. They are havens for critters big and small. The ongoing drought and the beetle infestations in parts of the region have alerted a lot of us to the potential for rapid change in these important ecosystems. I was reminded of that fact on our last day in the field when we spotted (and smelled) smoke near Long Lake in the southern Chuskas. As I write this the Assayii Lake Fire is 90% contained, but the fire burned nearly 15,000 acres of Chuskas forest. Chris's research won't prevent devastating fires, but marrying the science to management concerns the way that he has in this project is sure to promote a lot of mutual learning that—I'm convinced—is our best hope of making the research we do more useful to people who want to use it.

Chuska Mountains, Navajo Nation - Photo by Dan Ferguson

Dan Ferguson is the program director of the Climate Assessment for the Southwest (CLIMAS).