Abnormal snowpack melt in California, western U.S. increases wildfire and drought risks
The snowpack in California and other western states is melting at a record-breaking pace despite above-average snowfall in many areas, threatening an early start to the wildfire season and the persistence of drought conditions, authorities announced.
The National Integrated Drought Information System issued an update Tuesday warning of the rapid snowmelt because of above-normal temperatures and below-normal precipitation in April and May. The NIDIS said nearly all western basins are in late-season snow drought, an abnormally low snowpack for the time of year, even in areas that reached near to above-average water content in the snowpack during the winter.
The rapid depletion of snow, along with increased evaporative demand - or how "thirsty" the atmosphere is for water - can quickly dry soils and vegetation and lead to the fire season's early start.
"Snowmelt this time of year is common, but such rapid melt rates are not normal," the report stated.
In some instances, the conditions can cause snow to transition from a solid to a gas, reducing the runoff into streams and reservoirs, according to the report.
Stations in Nevada, Colorado, Utah, and New Mexico saw record early melt out, the report said. These areas, along with Southern California, Arizona, and portions of Washington, are locations where drought is likely to persist. Heightened wildland fire risk is also expected in California's Sierra Nevada and other areas of the state, as well as in Arizona, New Mexico, Utah, Colorado, southern Nevada, eastern Washington, and northern Idaho.
The 6-10 day outlook from the National Oceanic and Atmospheric Administration's Climate Prediction Center indicates above-normal temperatures across most of the West, which would accelerate snowmelt rates at the higher elevations where snow remains.
