NOAA's National Centers for Environmental Information
According to NOAA's National Snow Analysis, it was a slow start to the beginning of the 2023-24 snow season with less than one percent of snow cover across the contiguous U.S. (CONUS). On October 13, a storm brought snow to small portions of the northern Cascades and northern Rockies, increasing the snow coverage to 3.4 percent of the CONUS. Snow cover decreased steadily over the next week, reducing the snow cover to nearly zero percent of the CONUS. Snow cover remained minimal until a storm brought heavy snow across much of the West, which peaked to nearly 18 percent — the maximum snow cover extent for the month — on October 30. Snow covered much of the Cascades, Bitteroots, Rockies and in northern parts of the Plains, Great Lakes and Northeast. Snow cover decreased slightly on the final day of the month, as snow covered parts of the mountainous West, northern Plains, Great Lakes and northern parts of New England. By October 31, snow covered 17.5 percent of the CONUS.
According to NOAA data analyzed by the Rutgers Global Snow Lab, the October snow cover extent was 111,600 square miles, 32,000 square miles above the 1991-2020 average, and the 11th-highest value in the 56-year satellite record. Above-average snow cover was observed across much of the central and northern Plains and northern Rockies. Below-average snow cover was observed across parts of the Sierras, central Rockies and central Plains.
Melting of winter and spring mountain snowpack provides a crucial summer water source across much of the western United States. The total annual water budget for agriculture and human use in the mountainous West is highly dependent on the amount of snow melt that will occur in spring and is proportional to the amount of snow on the ground, which can be approximated by a measure of the snow water equivalent (SWE).
On October 31, with October marking the beginning of the snow season across the Lower 48, SWE values were at or above 150 percent of the median across much of the Cascades, Bitteroots, Sierras, Great Basin and in parts of the central Rockies, while much of the Rockies were near- to below-normal during the month. It is important to note that since it is early in the snow season, normal median values are typically low, which can result in unusually high percent of median values when snow does fall.