Snow conditions less volatile than the stock market

March 2025 snow summary 

• Snow-covered area across the western United States was 92 percent of average for March, ranking seventeenth in the 25-year satellite record. 

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

• Snow albedo, also known as snow brightness, started low in early March and then oscillated between high, then low, and back to high during the month.

• Snow water equivalent (SWE) relative to average showed little change during the month, despite SWE gains at many stations across the region.

Overview of conditions

Snow-covered area in March across the western United States was 8 percent below average, at 472,000 square kilometers (182,000 square miles) of snow cover, ranking seventeenth in the 25-year satellite record (Table 1). Snow-covered area for March was 670,000 square kilometers (259,000 square miles) below 2023, the highest year, and 224,000 square kilometers (86,000 square miles) above 2015, the lowest March on record.  

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

Snow cover was below average in most states during March (Figure 1). In the southwest, although conditions improved since February, snow cover was still below average in New Mexico (48 percent of average) and Arizona (86 percent of average). Below average snow cover was also observed in Colorado (80 percent of average) and Utah (88 percent of average), as well as Montana (90 percent of average), South Dakota (85 percent of average), and Wyoming (93 percent of average), indicating a decrease from the widespread February snow cover across the Northern Great Plains. Conditions were very close to average in California (102 percent of average) and Idaho (99 percent of average), with above-average conditions in Nevada (122 percent of average), Oregon (154 percent of average), and Washington (114 percent of average). These geographic patterns are also apparent in major river basins, with the lowest below-average snow cover in the Rio Grande (66 percent of average), Arkansas-White-Red (69 percent of average), and Missouri (78 percent of average) basins. In the Lower Colorado basin, snow cover was 95 percent of average, representing a significant shift compared to February when snow cover was at just 10 percent of average.  

Snow-covered area in March was near average across the western United States (Figure 2, upper left). March started with snow cover below the seventy-fifth percentile of the 25-year satellite record, but storms during the first week brought snow-covered area up to average. Snow-covered area then decreased to below average until snowstorms in mid-March brought snow cover back to average. For the remainder of March, snow cover decreased but still stayed near average. 

On the state level, vast low-elevation regions in Oregon had 40 to 80 percent above-average snow cover. By contrast, in Colorado, Utah, and southern Wyoming, snow cover fell 40 to 80 percent below average (Figure 2, upper right). California and Nevada had near-average snow cover, with the lowest elevations accumulating snow at 20 to 40 percent above average. Other regions had mixed conditions, with the tendency for below-average snow cover at higher elevations and above-average snow cover at lower elevations. 

Averaged over the western United States, the snow cover duration measured in days summed from October 1 to March 31 has continued to increase (Figure 2, lower left). Snow cover duration at the end of March was near the twenty-fifth percentile. Snow cover duration in Arizona, New Mexico, Nevada, and Utah was well below average, with widespread areas having 60 to 100 fewer snow cover days (Figure 2, lower right). Wyoming also had below-average snow cover duration. Conversely, Colorado, Oregon, Washington, Idaho, and Montana had regions with 20 to 40 more snow cover days than average. 

Average snow brightness, known as snow albedo, was 38 percent below average at the beginning of March, but storms early in the month increased albedo above the seventy-fifth percentile (Figure 3, left). High temperatures and snowmelt decreased snow albedo through the third week in March before storms at the end of the month increased snow albedo back to the seventy-fifth percentile. The San Juan mountains in Colorado, where dust storms often decrease snow albedo, had some of the cleanest snow in the satellite record through mid-March, but by the end of the month, dust was visible. Overall, the San Juans appear to have average albedo in March. 

Conditions in context: Snow water equivalent (SWE) 

Snow water equivalent (SWE) at the beginning of March was mixed with a range of average, below-average, and above-average values (Figure 3). Moderately to extremely low SWE was present in Arizona, New Mexico, southern Colorado, southern and central Utah, central Nevada, the Bighorn Range in Wyoming, lower-elevation stations in the Sierra Nevada in California, northwest Montana, and the Washington Cascades. SWE was near- or above-average in northern California, northern Nevada, the Front Range of Colorado, southern and eastern Oregon, and central Idaho.

Conditions remained relatively consistent through March. Relative to average, conditions at the end of the month looked very similar to the beginning of the month. Some low-elevation stations in the Sierra Nevada gained SWE but still ended the month with below-average conditions (i.e. shifted from dark red to light red). The Oregon Cascades and central Nevada also had modest SWE increases. Arizona and New Mexico had less SWE at the end of the month, with five stations dropping to 0 by March 31. 

Many regions recorded SWE gains in March (Figure 5). Coastal states in particular had large SWE gains, with some stations in Washington, Oregon, and California recording more than 40 centimeters (16 inches) of SWE accumulation (Figure 5, right). The Wasatch Range in Utah also gained SWE, partially because of lake-effect snowstorms. SWE losses were recorded in northern New Mexico, southern Colorado, and northeastern Oregon.