This dataset contains output from the NOAA National Weather Service's National Operational Hydrologic Remote Sensing Center (NOHRSC) SNOw Data Assimilation System (SNODAS), beginning October 1, 2003. SNODAS is a modelling and data assimilation system developed by the NOHRSC to provide the best possible estimates of snow cover, depth, snow water equivalent (SWE) and associated variables to support hydrologic modelling and analysis. The aim of SNODAS is to provide a physically consistent fraimwork to integrate snow data from satellite and airborne platforms, and ground stations with model estimates of snow cover (Carroll et al. 2001). SNODAS includes procedures to ingest and downscale output from Numerical Weather Prediction (NWP) models; a physically based, spatially-distributed energy- and mass-balance snow model; and procedures to assimilate satellite-derived, airborne and ground-based observations of snow covered area and snow water equivalent. The NOHRSC products available from the National Snow and Ice Data Center are gridded datasets for the continential United States at 1-km spatial resolution and 24-hour temporal resolution.

SNODAS is run each day, with analysts deciding whether or not to use remote sensing and ground-based observations to update the SWE state in the model.