News & Stories

Snow-covered area in March across the western United States was 8 percent below average, ranking seventeenth in the 25-year satellite record. Snow cover duration was just above the twenty-fifth percentile. Snow albedo, also known as snow brightness, started low in early March and then oscillated between high, then low, and then 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.

Arctic sea ice has likely reached its maximum extent for the year, at 14.33 million square kilometers (5.53 million square miles) on March 22, according to scientists at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder. The 2025 maximum sea ice extent is the lowest in the 47-year satellite record, falling short of the previous record low of 14.41 million square kilometers (5.56 million square miles) set on March 7, 2017.

Melting on the Antarctic Ice Sheet for the 2024 to 2025 season began with above average melt extents in all regions, but melt extent dropped to nearly zero or below average from February 1 to March 15. Net accumulation of snow, part of the ice sheet’s surface mass balance, was far above average for the year, helping reduce the ice sheet’s net contribution to sea level rise for this period.

Sea ice melt is not a significant contributor to sea level rise, but its contribution is not nothing, either. Sea ice is composed mostly of fresh water, which is less dense than salty ocean water. Consequently, sea ice melt produces water that takes up more volume than an equivalent weight of salt water, although the difference is minimal.

NSIDC expertise has contributed to the enhancement of Xarray, a popular open-source tool used for data analysis and visualization. DataTree has been integrated into Xarray.