Freshwater is a precious resource, especially in the arid and drought-prone Southwest. But what you may not know is that the biggest user of freshwater in the U.S. is not our everyday needs, or even farms, but power plants. What’s more, although 99 percent of those withdrawals nationwide were from surface water, in the Southwest, surface water is relatively scarce and thermoelectric power plants have been forced to use groundwater, which then raises concerns over aquifer depletion. (Read More)

The 12th and 13th century droughts during medieval times are perhaps the most well-recognized (see blog on 12/4/10). The medieval period in the Southwest, spanning roughly 800-1300 AD, is characterized by increased drought severity, duration, and extent. In a recent study using tree-ring chronologies from Colorado bristlecone pines however, Connie Woodhouse, Jonathan Overpeck, and I revealed an even earlier period of anomalous aridity and drought in the Southwest.( Read More)

Residents of the Southwest know the consequences of flooding all too well. Every year during the monsoon season, Arizona and New Mexico experience numerous storms that result in flooding, ultimately causing millions of dollars in damage and sometimes, sadly, fatalities. One good thing about these storms, however, is that the majority of the time we are somewhat prepared, in that locals are generally aware that flooding is likely during monsoon season. But what about storms that cause flooding during the rest of the year? (Read More).

Luckily, we’re pretty landlocked here in the Southwest, so unlike the East Coast, we don’t have to worry about hurricanes causing massive flooding and downing trees and power lines. Or do we? As it turns out, hurricanes and tropical storms in the eastern Pacific play a major role in our moisture budget and rainfall extremes. (Read More)

Many of us have seen the seasonal outlooks issued by the Climate Prediction Center (CPC) forecasters. These predictions are extremely important to those who have to make choices based on temperature and precipitation, such as natural resource managers, farmers, and ranchers. But there is a lot of information in the shading and numbers on these maps, and it’s not always clear what it all means. (Read More)

The monsoon is in full swing here in Tucson! Unfortunately, compared to the last two summers, this monsoon is looking somewhat better, but not by much (see recent CLIMAS report). This begs the question: is there any chance we could depend on the monsoon to help alleviate some winter water shortages in the future as global climate changes? (Read More)

We’re all itching to know if the monsoon will deliver this year, especially with the record wildfires, the widespread drought, and the closure of national forests across Arizona and New Mexico. Since our records of rainfall only go back to 1900, it’s hard to tell if the monsoon could get even stronger, or weaker, or if there could be periods of persistently strong or weak monsoons (e.g., ten years in a row of weak monsoons). To get at this information requires longer records of monsoon variability. Luckily, there are many archives of climate in the natural world. (Read More)

The impact of tropical Pacific ocean temperatures on the hydroclimate of the Southwest is profound: on timescales of 2-8 years, El Niño and La Niña events influence the amount of winter precipitation we receive. Trees living across the Southwest region record these changes in moisture in the width of their rings, providing us with a history of precipitation going back thousands of years or longer in some places. (Read More)