Snow surface energy exchanges and snowmelt at a continental, midlatitude Alpine site

The objectives of this study were to measure and evaluate the energy balance of a continental, midlatitude alpine snowpack during spring snowmelt conditions, to relate variations in the energy budget and snowmelt to synoptic weather patterns, and to evaluate the performance of a point energy and mass balance model of a snow cover (SNTHERM) in alpine conditions. The investigation was conducted during the 1994 snowmelt season at Niwot Ridge (3517 m above sea level (asl); 40°03′N, 105°35′W) in the Colorado Front Range. Net radiative fluxes and net turbulent fluxes respectively provided 75% and 25% of the total energy available for snowmelt during the season. Sublimation losses were limited to only 4% of the initial snow water equivalence at the site. The largest energy available for snowmelt was associated with a ridge in the upper airflow over the central and southern Rocky Mountains that permitted warmer air into the region. Using measured data from the study site, the SNTHERM model estimated the disappearance of the snowpack just 3 days earlier than the observed 42‐day ablation period.