#Drought-plagued #California and western U.S. may see another devastating fire season — The Washington Post

From The Washington Post (Diana Leonard and Becky Bolinger):

California and the West are falling deeper into drought and, with summer approaching, that portends another severe fire season.

As a disappointing wet season comes to a close and hope for spring rain fades, conditions are worse now than they were at this time last year, with exceptional and extreme drought now found throughout the region.

In California, that doesn’t bode well, given that last year’s more moderate rainfall deficits, combined with extreme heat waves, ushered in a record-setting fire year. It brought 5 of the 6 largest fires in modern state history, 10,488 destroyed structures and 33 fatalities. Some 4.2 million acres were torched.

More frequent drought, hotter summers and warmer and drier autumns, tied to climate change, are stacking the deck for large and destructive fires during the heart of the fire season. And this year, a lack of rain in spring could mean fires arrive early in some areas…

…despite a significant late-January storm [in California], the 2021 winter and spring months have failed to deliver even normal precipitation, and much of April is forecast to be very dry. In fact, the current water year is now tied for the third driest on record…

For the last two wet seasons, a persistent ridge of high pressure in the central and eastern Pacific has diverted most storms out of the state. In Northern California, many of the wettest, forested regions have missed over 20 inches of precipitation in that time period…

Statewide mountain snowpack, currently at less than 50 percent of normal, is expected to melt off early, leaving Sierra forests prone to burn earlier and hotter…

Drought deepens across the West, and fire risk follows

Large wildfires in the West are driven by a complex relationship between shorter-term weather and longer-term climate variability. The West’s descent into the current severe and widespread drought began in the fall of 2019, when a dry pattern emerged over Oregon, northern California, central Nevada and into parts of Idaho, Utah and Colorado. The hot and dry summer of 2020 quickly followed, which brought devastating fires to California and the Pacific Northwest, and set the stage for Colorado’s biggest wildfire season on record beginning in August and continuing through October…

This concerning situation continues: Not only is drought persisting over the same areas, it’s expanding to areas that weren’t as dry in the winter. Extremely warm and dry conditions from October to March extended across California and Oregon, and eastward across Idaho, Nevada, Utah, Arizona, and entering Wyoming, Colorado, and New Mexico…

Combining this longer-term climate signal with expected weather as we move into summer dictates the location of greatest fire risk. Based on low snowpack and early snowmelt already occurring in Arizona and New Mexico, and expected early snowmelt around the Four Corners, the risk for significant wildfires is high in Arizona and New Mexico, and is extending into southern Utah and southern Colorado. That risk moves northward as the summer continues into central Nevada, Utah and western Colorado, but should be reduced to the south if monsoon rains arrive as expected.