Abundant snowpack not uniform across Western U.S.
March 17, 2023
Snow drought in south Colorado and the Pacific NW
NOAA’s U.S. National Integrated Drought Information System (NIDIS) reports snow drought concerns in parts of the western region despite piles of snow across California and the Great Basin.
“Snow water equivalent (SWE) currently in the 10th to 20th percentile for the period of record” in Colorado’s Sangre De Cristo Mountains. Snowpack from south and south-central areas of the state drain into the Arkansas, White, and Red Rivers.
Across the Pacific Northwest, although “SWE ranges from 82%–133% of normal, dry soil moisture profiles, low streamflows, low water levels in many reservoirs, and below-normal water year precipitation raise concern about ongoing or worsening drought conditions. Meteorologists and climatologists continue to monitor spring precipitation.
As of March 12, 2023 about 19% of the western continental U.S. SNOTEL stations reported a “below median” snow water equivalent.
Across Alaska, SWE is “near to above normal with the exception of portions of the Kenai Peninsula, the North Slope, and the southwest coast west of Bethel, where levels are below normal.”
While water managers throughout California and the Great Basin welcome the deep snowpacks, flooding risk is elevated as forecasts of “warmer storms with high-elevation rain” will increase snowmelt runoff.
Automated snow monitoring is conducted by the USDA Natural Resources Conservation Service (NRCS) snow telemetry (SNOTEL) network, which is composed of more than 900 automated data collection sites located in remote, high-elevation mountain watersheds in the western United States. The stations record data on snow water equivalent, snow depth, all-season precipitation accumulation and ambient air temperature. Enhanced SNOTEL sites also monitor soil moisture and soil temperature, solar radiation, wind speed and relative humidity. SNOTEL data are transmitted to the centralized Water and Climate Information System, which is used to forecast water supply.