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Regional Drought Update Date
April 7, 2022
Site Section
Drought Status Update

Snow Drought Current Conditions and Impacts in the West


Update Status:

NIDIS and its partners release these updates every 4 weeks, December through June. 

Snow Drought Hits Most of the West for the Second Straight Year and California for the Third Straight Year

Key Points

  • Snow drought conditions remain widespread across the West and have generally become more severe over the past month. 
  • A lack of precipitation was one of the main drivers, with March bringing only about 25%–50% of normal precipitation to the Sierra Nevada, northwestern California, southern and eastern Oregon, and the Great Basin.
  • Except at the highest elevations, the start of April typically is associated with peak snowpack and the start of the snowmelt season, making recovery from snow drought difficult if not impossible at this point in the water year.

What Is Snow Drought? Learn More

Current Conditions
Current Conditions: Snow Water Equivalent (SWE)

Snow Telemetry (SNOTEL) snow water equivalent (SWE) values for watersheds in the western U.S. as a percent of the USDA Natural Resources Conservation Service (NRCS) 1991–2020 median. Only stations with at least 20 years of data are included in the station averages.

The SWE percent of normal represents the current SWE at selected SNOTEL stations in or near the basin compared to the average value for those stations on this day. This map is valid as of April 4, 2022.

For an interactive version of this map, please visit NRCS.

Snow Telemetry (SNOTEL) snow water equivalent (SWE) values in watersheds in Alaska as a percent of the USDA Natural Resources Conservation Service (NRCS) 1991–2020 median. Only stations with at least 20 years of data are included in the station averages.

The SWE percent of normal represents the current SWE at selected SNOTEL stations and Snow Course sites in or near the basin compared to the average value for those sites on this day. This map is valid as of the end of March 2022.

For an interactive version of this map, please visit NRCS

SWE Percent of NRCS 1991-2020 Median
Value Map Hex Color
> 150% #0100fe
130% - 149% #00a9e4
110% - 129% #70ffdd
90% - 109% #4ee504
70% - 89% #e6e500
50% - 69% #e39a00
< 50% #e80000
Main Stats
85%
of western CONUS station SWE is below median
60%
of western CONUS station SWE is below 30th percentile*

Snow Drought Update for April 7, 2022

Snow drought conditions remain widespread across the West and have generally become more severe over the past month. Snow drought currently is most extreme in the Sierra Nevada, northwestern California, southern and eastern Oregon, and the Great Basin, where snow water equivalent (SWE) currently is around 30%–60% of median. SWE in the Rocky Mountains in Wyoming, southwestern Montana, and southeastern Idaho is currently around 65%–80% of median. SWE at many stations in the region is below the 10th percentile, and several stations are at record low SWE for this date. SWE in the Cascade Range in northern Oregon and Washington is below normal (75%–90% of median). The Upper Colorado River Basin is 86% of the median. However, SWE in the basin is not distributed evenly. SWE in the northwestern basin in Utah and Wyoming is well below normal, whereas SWE in the San Juan Mountains in the southeastern basin is closer to normal. Except at the highest elevations, the start of April is typically associated with peak snowpack and the start of the snowmelt season, making recovery from snow drought difficult if not impossible at this point in the year. In Oregon, in the majority of the major basins, snow drought will be characterized by well below normal SWE combined with very early melt-out.

A lack of precipitation was one of the main drivers of the current snow drought. March precipitation was only about 25%–50% of normal in the Sierra Nevada, northwestern California, southern and eastern Oregon, and the Great Basin. This continued the trend of a dry calendar year and January–March cumulative precipitation at many SNOTEL sites in this region was record low. A prolonged heat wave across the West, but centered over California from March 22–27 accelerated early snowmelt and intensified snow drought conditions. For example, SWE in the Truckee River Basin, which drains Lake Tahoe and provides water to over a half million people, lost nearly six inches from March 22–27, and currently is just 48% of median.

Relative snow levels in Alaska are much better off than CONUS. Of the 149 sites reporting for the April 1 snow survey (SNOTEL and snow courses), only 9 were below 100% of median SWE, and only two were below 80% of median. This was one of the snowiest winters on record for parts of Alaska. 49 sites had record high April 1 SWE; these sites were concentrated in the Tanana River, Copper River, and Susitna River HUC6 basins. Tok Junction, in the Tanana River Basin, reported 8.8 inches of SWE on April 1 (259% of median), which was the highest since 1960 and shattered the previous high of 6 inches set in 1967.

Stations with SWE Below the 30th Percentile

A map showing snow water equivalent percentiles for SNOTEL and other Cooperative Snow Sensor stations in the Western U.S. The scale ranges from 0 (dark red) to 30 (yellow). Locations with low SWE values are located in most western states.
Snow water equivalent (SWE) percentiles for locations in the western U.S. at or below the 30th percentile as of April 4, 2022. Stations above the 30th percentile* are shown with a black “x”. Only SNOTEL and other Cooperative Snow Sensor stations with at least 20 years of data were used. Data Source: USDA Natural Resources Conservation Service.

Water Year Accumulated Snow Water Equivalent in the Truckee Basin

Time series graphs showing the water year from October 1 through September 30 for the Truckee Basin with water year accumulated snow water equivalent. Current SWE values are below median.
USDA Natural Resources Conservation Service (NRCS) water year accumulated snow water equivalent (SWE) in inches (black) in the Truckee Basin compared to the 1991–2020 maximum (blue), median (green), and minimum (red). Graphics can be found at NRCS

* 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

Special Thanks

NIDIS and its partners launched this snow drought effort in 2018 to provide data, maps, and tools for monitoring snow drought and its impacts as well as communicating the status of snow drought across the United States, including Alaska. Thank you to our partners for your continued support of this effort and review of these updates. If you would like to report snow drought impacts, please use the link below. Information collected will be shared with the states affected to help us better understand the short term, long term, and cumulative impacts of snow drought to the citizens and the economy of the regions reliant on snowpack.

Report Your Snow Drought Impacts     Data and Maps | Snow Drought     Research and Learn | Snow Drought