Thursday, March 18, 2021

Much of Western U.S. still gripped by mega-drought as precipitation window closes; more wildfires expected

Drought conditions in Western U.S. as of March 16, 2021;
darkest colors are driest. (U.S. Drought Monitor map)
"Almost 80 percent of the Western U.S. is in drought, with nearly 42 percent of the region in 'extreme' or 'exceptional' drought," Becky Bolinger and Andrew Freedman write for The Washington Post. Bolinger is assistant state climatologist for Colorado and a Colorado State University research scientist.

"Much of the region experienced developing drought in the summer, following a warm and dry spring. Since then, conditions have deteriorated, and the precipitation deficits continue to build," they write. "At its maximum extent in January 2021, 47 percent of the West was in extreme drought or worse. Nearly a quarter of the area was in the worst drought category, an event with a probability frequency of once every 50 to 100 years."

Though the Pacific Northwest got more than 10 inches of precipitation last month, "much of the interior Rockies through Idaho, Montana, Wyoming, Utah, and Colorado received between 1 and 5 inches of moisture for the month," Bolinger and Freedman report. "The Sierra Nevada in California received between 2 and 6 inches, much of that in the form of snow." 

However, many areas are still facing a significant deficit in precipitation. "The evidence is clear — February was beneficial for many, but it was not a drought-buster, and drought continues to maintain its stranglehold on the West," Bolinger and Freedman report. "It’s increasingly likely severe drought will continue in other parts of the West as we head toward summer. Agriculture, water supplies, and forests are likely to be impacted. Expect crop losses and selling of livestock; watering restrictions may begin as temperatures warm, and the risk of large wildfires will return again this summer."

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