About this Map:

The annual snowfall map was developed by the Baltimore/Washington National Weather Service Weather Forecast Office. The map was constructed from a combination of datasets including the 1981-2010 climate normals from the National Climatic Data Center (NCDC) (http://www.ncdc.noaa.gov/oa/climate/normals/newnormals.html) and 1981-2010 PRISM data from Oregon State University (http://www.prism.oregonstate.edu). Snowfall data, which was extracted from the NCDC climate normals dataset, represents the latest three-decade climate average at Cooperative Observer Program (COOP) stations. PRISM data uses a vast collection of point data as well as a digital elevation model to develop a gridded map of climate parameters. Interpolation methods in a Geographic Information System (GIS) were used to combine the NCDC snowfall data and gridded PRISM precipitation data, and subsequently develop a gridded map of normal annual snowfall for the Mid-Atlantic region. Select station snowfall values are rounded to the nearest whole number when displayed on the map.