Mean Monthly and Annual Snowfall
Conterminous United States

Statistic: 30-year average snowfall (depth of freshly fallen snow) 
Time period: 1961-1990
Time interval: monthly
Spatial format: grid
Data format: ARC/Info ASCII GRID

Projection: Geographic
Spatial resolution: 1.25 arc-minutes (~2 km)
Spatial Extent: Conterminous United States
Units: Millimeters

Date created: August 2000
Methods: Statistical derivation from mean monthly and annual precipitation and wet-day temperature, mapped with the PRISM modeling system and Gaussian filter resolution enhancement. See FGDC-compliant metadata for details. 


Mean annual snowfall
  • Reviewed and approved by the US National Climatic Data Center and regional experts 
  • Incorporates topographic effects on snowfall 
  • Captures rain shadows in great detail 
  • Includes coastal and lake effects on snowfall 
  • Accounts for the varying ability of terrain features to enhance snowfall 
  • Consistent treatment and spatial quality control of station data 
  • Consistent coverage across all state boundaries 
  • "Universal" geographic (latitude/longitude) projection allows conversion to any other coordinate system 
  • Data format allows for easy import into ESRI's GIS products, as well as MAPINFO and Intergraph's GeoMedia 
Data used in analysis
  • 7,349 National Weather Service stations for snowfall 
  • 9,110 stations for mean precipitation 
  • 6,358 stations for mean wet-day temperature
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