Snow Drought Current Conditions and Impacts in the West

Snow Drought Update for February 10, 2022

The faucet has been shut off across much of the West over the past month after a promising wet and snowy start to the season. Well above-normal snow water equivalent (SWE) at the start of 2022 provided the buffer needed to mitigate the extreme dry spell over the past month and avoid a rapid plunge into a snow drought across most of the region. A persistent ridge of high pressure has been parked off the West Coast since early January, leading to record-low precipitation totals at SNOTEL sites over the past 30 days in every western state except for New Mexico. Zero precipitation was observed over the past 30 days at many SNOTEL sites in northwest California, the Sierra Nevada, and the Great Basin. Remarkably, some of the sites at which zero snow fell in the past month still have slightly above-normal SWE thanks to major storms during the last two weeks of December and beginning of January. Still, the West as a whole is trending toward snow drought conditions, with below-normal SWE at 62% of the SNOTEL sites on February 8 compared to 21% on January 10 

As we progress through the snow season, attention turns to spring runoff and summer water supply. Peak SWE is one of the metrics used to assess potential water supply outcomes. The timing of median peak SWE varies across the West, but generally occurs from late March through early April, with higher-elevation sites in the Rockies peaking the latest. With over a month left in the heart of the snow season, many areas have already exceeded 70% of median peak SWE thanks to the wet period in early winter. In the Cascade Range of northern Oregon, several SNOTEL sites, mostly at lower elevations, have already exceeded the median peak SWE, which is encouraging. Areas in which values of less than 50% of median peak SWE are widespread include northwest California, northeast Nevada, Utah, northwest Wyoming, and southwest Montana. Forecasts indicate that below-normal precipitation and snowfall is likely to continue during the next 1–2 weeks over most of the West. The continued dry spell, above-normal temperatures, and increasing late winter sun angles all will be working against snowpack accumulation, and the spatial extent of snow drought is likely to continue to increase.  

Snowpack across most of Alaska (where there are observations) continues to be above normal, with a few exceptions. A cluster of four SNOTEL stations in the Kenai Mountains north of Seward have slightly below normal SWE (82%–96% of normal). SWE is also below normal in the Chugach Mountains near Thompson Pass as indicated by the Upper Tsaina River SNOTEL and several early February snow course readings in the area. Record high (40–60 year period of record in some cases) early February SWE was measured throughout the Central Interior and in the upper Susitna Basin near Lake Louise.

Stations with SWE Below the 30th Percentile

30-Day Precipitation Records: January 9–February 7

Percent of Median Water Year Peak Snow Water Equivalent

* Quantifying snow drought values is an ongoing research effort. Here we have used the 30th percentile as a starting point based on partner expertise. Get more information on the current definition of snow drought here. 

For More Information, Please Contact:

Daniel McEvoy
Western Regional Climate Center
Daniel.McEvoy@dri.edu

Amanda Sheffield
NOAA/NIDIS California-Nevada Regional Drought Information Coordinator
Amanda.Sheffield@noaa.gov

Britt Parker
NOAA/NIDIS Pacific Northwest and Missouri River Basin Regional Drought Information Coordinator
Britt.Parker@noaa.gov