Snow drought persists in parts of the US West, after April warmth accelerates snowmelt

The effects of a “snow drought” are still plaguing parts of the U.S. West, after a stretch of warm, dry weather last month accelerated the season’s snowmelt, federal meteorologists reported. 

While California’s Sierra Nevada has received sufficient snow this season to escape such a designation, the same cannot be said for areas in the northern Rocky Mountains and Washington State, according to an update issued on Wednesday.

In those areas, which are enduring “the most severe snow drought,” snowpack at many lower elevations has melted one to four weeks early, per the National Oceanic and Atmospheric Administration (NOAA) and the National Integrated Drought Information System (NIDIS).

“Western snowmelt season is well underway,” the meteorologists stated. 

NOAA and NIDIS define a “snow drought” as a period in which there are abnormally low levels of mountain snow accumulation, or snowpack, which serves as a water reservoir for much of the West during the spring and summer seasons. 

Meanwhile, a period of warm weather and dry conditions in mid-April triggered what the meteorologists described as “rapid snowmelt in the Southwest, especially in southern Colorado and New Mexico.”

Measurements at about 45 percent of U.S. West stations that monitor snow-water-equivalent — the amount of water contained in snowpack — were lower than the 1991-2020 median as of May 5, according to the NOAA and NIDIS update.

While concluding that the snow drought has expanded in parts of the U.S. West due to the early and rapid snowmelt, the meteorologists stressed that “conditions are evolving.”

“Tracking snow drought during this time period helps to evaluate potential impacts to summer water supply, soil moisture and vegetation conditions,” they added. 

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