Gridded snow water equivalent estimation using ground-based and airborne snow data

The National Weather Service (NWS) has developed a methodology to generate real-time gridded (1km) snow water equivalent estimates using ground-based and airborne snow data. The gridded snow water equivalents incorporate the spatial variability of the snowpack induced by orographic effects in the West. A baseline system is currently being implemented by the NWS over the Colorado River basin above Lake Powell.The Snow Estimating and Updating System (SEUS) uses a geographic information system (GIS) to store, analyze and display gridded, point and line data, such as elevation, basin boundaries and snow observations. The system has a calibration component to define basin-specific parameters, and an operational component to ingest real-time data and calculate gridded snow water equivalent estimates, and updating component to incorporate the ground-based snow water equivalent estimates into a conceptual hydrologic model. This paper reviews the system implementation and the results of operational testing during the 1993 snow season.