National Snow and Ice - Annual 2015
NCEI added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
The 2014/15 winter season (December 2014-February 2015) was marked by much warmer than average conditions during the first half of the season and cooler than average conditions the second half. February was extremely cold across the eastern half of the contiguous U.S. with 29 states being much cooler than average, while the West was extremely warm with eight states being much warmer than average. For the season as a whole, 11 states in the West were much warmer than average, including six states being record warm. The record and near-record warmth in the West was associated with much below-average snow cover and snowpack during the season, while the cold end to winter brought above average snowfall to much of the Midwest and Northeast. This pattern, of a warm West and cool East, continued into early spring. The cold late-winter and early-spring temperatures combined with an active storm pattern brought a tremendous amount of snowfall to coastal New England. Boston, Massachusetts received 110.6 inches of snow during the snow season, surpassing the record of 107.6 inches in 1995-96. Most of the snow during the season fell during late winter and early spring, with snow remaining on the ground in some places until June.
Contiguous U.S. Winter Snow Cover Extent Anomalies
Data Source: Rutgers Global Snow Lab
According to NOAA data analyzed by the Rutgers Global Snow Lab, for the winter season, the contiguous U.S. snow cover extent was 62,000 square miles below the 1981-2010 average; this was the 23rd largest (27th smallest) winter snow cover extent for the contiguous U.S. and the smallest since the winter of 2011/12. The heavy late-season snow in the East was not enough to compensate for the lack of snow in the West. On the monthly scale, the December and January snow cover extents were below average, while the February snow cover extent was above average. For the spring season (March-May), the contiguous U.S. snow cover extent was 362,300 square miles below the 1981-2010 average. This was the smallest spring snow cover extent in the 49-year period of record. The previous record low spring snow cover extent occurred in 1968. Snow cover was much below average during March, April, and May, with monthly rankings of fifth smallest, ninth smallest, and 18th smallest, respectively. During each month, much below-average snow cover was observed across the western half of the nation, with above-average snow cover in parts of the Midwest and Northeast.
In Alaska, the snow cover extent was mixed during the winter and spring. Early in the winter, snow cover extent was above average, but warm and dry conditions limited snow cover from February to May. The December and January snow cover extent for the state was slightly above average. By February, the snow cover extent was below average, which continued into early summer. The snow cover extent from April through June was among the five smallest for each month and was record small for June. A warm spring limited the amount of frozen precipitation that fell across the state during the second half of the season. The lack of snow in southern Alaska prompted the move of the iconic Iditarod race over 200 miles northward. This was only the second time the race had to be moved northward due to lack of snow, with the first being in 2003.
Western U.S. Snowpack
April 1, 2015
Winter and spring mountain snowpack provide a crucial 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. The annual snow pack typically peaks in early April. As of April 1st, most locations from the Great Basin to the West Coast had much below-average snow pack. In the Cascade and Sierra Nevada Mountains, snow pack totals were less than 25 percent of normal and record low for several locations. For parts of California, this marks the fourth consecutive spring with much below average snow pack, causing significant concerns for water resources going into the warm and dry season. Please visit our supplemental page for additional information on April 1st snow water equivalents across the region. Snow pack was also less than 25 percent of normal for much of the Great Basin and southern Rockies. Near-average snow pack was observed in the Central and Northern Rockies. In Alaska, snow pack totals less than 25 percent of average were observed across southern regions of the state, while interior locations had near-average snow pack.