Widespread snow, limited water

• Snow-covered area across the western United States was 87 percent of average for February, ranking sixteenth in the 25-year satellite record. On February 18, snow-covered area reached its maximum for the season.

• Snow cover duration was just above the twenty-fifth percentile of the 25-year satellite record.

• Snow albedo, also known as snow brightness, was low in early February. By mid-month, snowstorms increased the brightness, only to rapidly decrease to a seasonal low at month's end.

• Snow water equivalent (SWE) was below average for 76 percent of stations at the beginning of the month and 59 percent at the end of the month.

• Nearly all SWE stations across the western United States reported gains in February, except for a few low-elevation stations primarily in the deserts of the Southwest. 

Overview of conditions

Snow-covered area in February across the western United States was 13 percent below average, at 822,000 square kilometers (317,000 square miles) of snow cover, ranking sixteenth highest in the 25-year satellite record (Table 1). Snow-covered area for February was about half of the area of the record high year, 2023, and 264,000 square kilometers (102,000 square miles) more than February 2003, the lowest year on record.

Table 1. February 2025 Snow Cover in the Western United States (Relative to the 25-Year Satellite Record)

Based on the 25-year satellite record, maximum snow cover occurred on February 18, 31 days later than average and six days earlier than 2018, the year with the latest date of maximum snow cover on record (Figure 1).  

Snow cover extent was mixed across the region in February (Figure 2). Snow cover was far below average in the Southwest, at 18 percent of average in New Mexico and 8 percent of average in Arizona. This pattern extended into the deserts in southern Utah (60 percent of average) and Colorado (76 percent of average), contributing to below-average snow cover in those states. Conditions were closer to average for this time of year in California (88 percent of average) and Wyoming (98 percent of average). Further north, widespread snow cover from coastal regions through the Northern Great Plains resulted in above-average snow cover in Washington (154 percent of average), Oregon (162 percent of average), Idaho (109 percent of average), Montana (189 percent of average), and South Dakota (112 percent of average). These geographic patterns are also apparent in major river basins, with far below-average snow cover in the Rio Grande (37 percent of average) and Lower Colorado (10 percent of average) basins and above-average conditions in the Missouri (135 percent of average) and Pacific Northwest (130 percent of average) basins.  

Conditions in context: Snow cover

Snow-covered area in February was below average but above the lower twenty-fifth percentile (Figure 3, upper left). During February, snowstorms greatly increased snow-covered area to above the upper seventy-fifth percentile of the 25-year satellite record. Snow-covered area decreased rapidly in late February, ending below the twenty-fifth percentile. In southern regions, snow-covered areas at low and mid-elevations were 40 to 80 percent below average with higher elevations having 1 to 40 percent below-average snow cover (Figure 3, upper right). In northern regions, lower to mid-elevations had 20 to 100 percent above-average snow cover while high elevations had 1 to 20 percent above-average snow cover. 

Averaged over the western United States, the snow cover duration measured in days summed from October 1 to February 28 has continued to increase (Figure 3, lower left). Typically, in October through January in any given year the minimum snow cover duration and the twenty-fifth percentile have similar trajectories. By contrast, in February, the two begin to move apart. This year, February snow cover duration was near the twenty-fifth percentile with the most recent storms in February pushing snow cover days slightly above the twenty-fifth percentile. Despite the previously-discussed high snow cover percent for February in the northern regions (Figure 3, upper right), snow cover duration was slightly below average (-1 to -40 percent) in the majority of areas (Figure 3, lower right). February snowstorms accumulated snow cover at low elevations that was short lived because of warm conditions. The southern regions had below average snow cover duration in nearly all locations except the Front Range in Colorado, which had up to 60 days more snow cover, while high elevation ranges had up to 40 days more snow cover. 

Average snow brightness, known as snow albedo, was five percent below average at the beginning of the month (Figure 4, left). Snowstorms temporarily brightened the snow albedo to above average before rapidly decreasing in late February. There were also a few days when many low elevation areas were blanketed with bright snow that have been historically snow free. This led to vast regions of above average snow on the spatial maps (Figure 4, right). However, this low-elevation snow did not linger long enough to darken. By the end of February, average snow-covered area was just below the twenty-fifth percentile (Figure 3, upper left). 

Conditions in context: Snow water equivalent (SWE) 

By the end of the month, only 59 percent of stations reported below-average SWE. SWE stations that shifted from below-average to near- or above-average are distributed throughout the Wasatch and Uinta Ranges in northern Utah, the Sierra Nevada Range in California, and the Greater Yellowstone Ecoregion across Wyoming, Montana, and Idaho. Mountain regions in the desert southwest (Arizona, New Mexico, southern Utah, and southern Colorado) and northern Washington saw little snow accumulation throughout February, and SWE deficits were largely maintained in these regions. At the end of February, 13 stations in Arizona and 13 stations in New Mexico reported 0 SWE. 

Although SWE at the end of February was still below average at more than half of stations, nearly all stations recorded SWE gains during February (Figure 6). Atmospheric river events brought substantial precipitation to California, Washington, and Idaho. At some stations SWE gains of more than 50 centimeters were recorded. With assumed snow density of 15 percent, this represents more than 10 feet of snowfall during February at those stations. SWE losses were confined to low elevation stations, primarily in the desert southwest region.