SNOWPACK AND THE SUBNIVEAN ENVIRONMENT FOR DIFFERENT ASPECTS OF AN OPEN MEADOW IN JACKSON HOLE, WYOMING, USA

Snowpack characteristics of an open meadow habitat were examined by students of the Teton Science School's Winter Ecology Course. Characteristics evaluated are inherent in snowpacks throughout circumpolar regions. Snowpits were sampled for 9 yr on a north-facing slope, a valley bottom, and a south-facing slope (situated in the same locations all years). Snow was deepest on the north-facing slope and shallowest on the valley bottom each year. Snowpack thermal index values less than 200 in some years in the valley bottom and on the south-facing slope indicated a possible failure to provide temperature buffering of the nivean environment. Despite lower air temperatures, ground temperatures of the north-facing slope snowpits appear to be higher than the other two aspects, especially in colder years. Temperature gradient snow (TG, depth hoar, or pukak) was well developed in all years for all aspects. We speculate that the depth of formation of cohesionless TG crystals has been sufficient for small mammal movement beneath the snow in all years. Snowpacks with little temperature buffering capability (indicated by low thermal indices), however, may discourage usage of certain locations by mobile mammals in some years. Fluctuating ground temperatures may also influence plant species composition and distribution beneath the snowpack.