The Northwest Avalanche Center, an integral part of NOAA and the National Weather Service, is a good source
for past observations, snowpack summaries and other snow/high country related data.NOAA's NOHRSC Resources...
The interactive website includes time series plots of modeled and observation data for stations, the ability to choose physical elements and shapefile overlays to display images, and create basin averaged text and map products.
The national and regional snow analyses provide daily comprehensive snow information for the coterminous United States. The products include daily regional maps, text summaries, and model analyses.
The airborne snow survey page includes current survey information, schedule of surveys, historical and current airborne gamma data, and background information for the Airbrone Gamma Snow Survey program.
www.weather.gov 
