Modeling snowpack accumulation patterns in Idaho with a geographic information system

The West's high mountain ranges hold a vast snowpack that provides 50 to 80 percent of the yearly water supply. The Natural Resources Conservation Service has measured snow accumulation at over 200 snow courses in Idaho for more than 30 years. With these data, this study describes the spatial and temporal characteristics of this crucial water resource component by modeling snowpack accumulation patterns in Idaho. Multiple regression analyses were run by watershed. Monthly long-term mean snow water equivalents (SWE) and yearly April SWE were used as the dependent variables. A number of independent variables were derived from the digital elevation model by a geographic information system (GIS). The regression models were used to make SWE surfaces, from which SWE distribution maps were produced. SWE surfaces also allowed estimation of the total amount of SWE by watershed using the GIS. Multiple regression analysis was helpful for modeling snowpack accumulation patterns, given the sparsely, non-randomly, and non-regularly distributed snow course data. Also the cell-based GIS has proved to be a very powerful tool in spatial analysis.