National Snow & Ice - January 2013
During January, much of the eastern U.S. was warmer than average while the West was cooler than average. Precipitation was more of a mixed bag with wetter-than-average conditions stretching from the Southern Plains into the Midwest and Mid-Atlantic while much of the West, Southeast, and Northeast were drier than average. According to NOAA’s National Snow Analysis, at the beginning of January, 66.6 percent of the contiguous U.S. had snow on the ground — the high terrain of the West and Great Basin, the Northern and Central Plains, the mid-Mississippi and Ohio river Valleys, the Great Lakes and much of the Northeast. The nature of the large January 1st snow cover was somewhat deceiving as many locations across the Great Plains, Midwest, and Northeast that did have snow on the ground had below-average snow depth. By January 31st, 44.6 percent of the contiguous U.S. was snow covered — the high elevations of the West, the Northern Plains, Western Great Lakes, and northern New England.
U.S. January Snow Cover Extent Anomalies
Source: Rutgers Global Snow Lab
According to data from the Rutgers Global Snow Lab, above-average January snow cover was observed for much of the western United States, as well as parts of the Northern Plains and Midwest. Below-average snow cover was present for the Central and Southern Plains, the Southern Rockies, and the Ohio Valley. The above-average snow cover for the West was due more to below-average temperatures preventing melting of December snowfall than new snow during January. As a whole, the contiguous U.S. experienced slightly above-average January snow cover. The monthly average snow cover extent of 1.44 million square miles was 104,600 square miles above the 1981-2010 average.
1 February Mountain Snowpack
According to data from the U.S. Department of Agriculture (USDA), snowpack across the western U.S. was mixed during January. As of February 1st, above-normal snowpack was observed across the Northwest with parts of the Cascades having snowpack totals more than 180 percent of normal. Snowpack was below average for the Central and Southern Rockies stretching from Wyoming to Arizona with some locations have less than 50 percent of normal snowpack. Most other locations in the West had near-normal snowpack totals. Across Alaska, below-average snowpack was present for large areas of the state including the southern coast and interior regions. Above-normal snowpack was observed along the Alaskan panhandle.
Summary of Notable Snow Events:
Satellite Image of Lake Effect Snow Band
over Lake Ontario and New York
Source: National Weather Service
January was marked by large temperature swings, particularly east of the Rockies. These swings in temperature were associated with strong cold fronts traversing the country. Ahead of the cold fronts, warm temperatures surged northward while along and behind these fronts, snow and cold temperatures were observed. For most locations, these shots of cold air and snow were short lived with only minor snow accumulations observed. These storms were partially responsible for the large snow cover extent, while snow depths were several inches below average across the Great Plains, Midwest, and Northeast. The exception was the lake effect snowfall across parts of the Great Lakes region when the cold air outbreaks moved over the warm and mostly ice free Great Lakes. Some locations in New York received over 3 feet of snow during these lake effect events.