Snowmelt runoff models simulate the spring runoff, an important part of the hydrologic system of Alaska's arctic coastal plain. The snowmelt model produces a snowmelt hydrograph which is converted by the runoff model into a runoff hydrograph. The snowmelt model subdivides the snowpack into two layers. Daily climatological parameters govern the heat transfer between snowpack and atmosphere. Once the heat flux received or emitted by the snowpack has been computed, the melting processes within the snowpack are considered. Computed parameters of the snowpack are density, depth, water equivalent, water content, temperature, and thermal quality. The runoff model uses a three-parameter linear storage model to transform the snowmelt hydrograph into a runoff hydrograph.