The effect of ski run cutting and artificial showmaking on snow water accumulation at Big Sky Ski area, Montana

This study examines the effect of forest clearing for ski runs and artificial snowmaking on snow water accumulation at of Big Sky recreation area in southwest Montana. Extensive research shows that clearing the forest canopy for timber harvest increases water stored in the snowpack, but no studies have compared water stored in the compacted, skied, and machine groomed snowpack of ski runs with the water stored under the natural forest canopy. Thirty six sampling locations were selected, terrain variables (elevation, aspect and slope angle) were surveyed, and snow depth, density and water equivalence were measured both under the forest canopy and on the adjacent ski run. Additionally, some of the sampling locations were in areas with artificial snowmaking. Snowpack on the run has a higher density and water equivalence, and a similar depth, to snow off the ski runs. Elevation is the primary terrain variable that affects snowpack characteristics, and increases in snow water equivalence (SWE) with increasing elevation are similar to previously published research. There was no significant difference between snow water storage on ski runs with snowmaking and those without snowmaking, although the snow density on the runs with artificial snow was higher. Total increase in snowpack water storage for all ski runs at Big Sky was greater than 700,000 m3. This number is close enough to values derived from a model designed to measure water yield due to forest cutting that it appears that the clearing of ski runs causes similar increases in snowpack water storage and water yield as forest clearing for timber harvests.