Coupled model simulation of snowfall events over the Black Hills

Snowfall over the higher terrain of western mountain regions is critical for water resources in these regions. The Upper Missouri River Basin Pilot Project was carried out in April and May 1999 in the Black Hills of South Dakota. This project provided an excellent observation data base for studying orographic snowfall, snowmelt and runoff processes. Numerical simulations were run for the April 10-12, 1999 snowfall event with a coupled atmospheric surface and subsurface hydrologic model (CAHMS).

Results of simulations will be presented which will describe the atmospheric simulation of the storm and precipitation, the subsequent snowmelt, and runoff. Results will be compared to observations. Comparison of different treatments of the snowpack will be compared with observations with respect to timing and rate. The influences of slope factor and internal heat transfer in the snowpack on the results will be discussed. Effects of differences in snowpack evolution on feedbacks to the atmosphere will be considered.