The Snow Mass Balance of Wolf Creek, Yukon: Effects of Snow Sublimation and Redistribution

Snow cover is not only a major hydrological input to the Wolf Creek Research Basin but provides a habitat for life and sustains important interactions with vegetation and climate. The losses or gains of snow within the basin and to and from the basin are therefore extremely important for the hydrology, biology and climatology of the region. This paper will review a four year record of snow studies in Wolf Creek. The sites are in the alpine, shrub-tundra and boreal forest vegetation bands of the basin and are representative of tundra plateaux, valley shrub-tundra and lowland forest respectively. At the alpine and shrub-tundra sites, wind speed, blowing snow occurrence, snow depth, temperature and humidity were measured half-hourly and snowfall and snow accumulation on the ground measured monthly. These measurements permit a mass balance of snow transformations due to blowing snow on the alpine plateaux and shrub-tundra valleys of Wolf Creek Basin. The measurements show that on average 50 % of snowfall is removed from the alpine plateau and 25 % is removed from low-lying shrub-tundra by blowing snow storms. Much of this snow is relocated to hillsides where it can triple snow accumulations. However, though some blowing snow is lost to sublimation, the proportion cannot yet be quantified in mountainous terrain. At the forest site, snow surveys under the canopy were compared to snowfall records in order to estimate snow interception storage and eventual sublimation. Snow remains in the canopy for weeks to months in the cold mid-winter. From 38%-45 % of annual snowfall is lost to snow sublimation from spruce canopies in the lower elevations of Wolf Creek. The implications of these results are that the snow cover of Wolf Creek is controlled by its vegetation cover, exposure and climate. Changes to land use or climate in the Yukon will therefore have profound changes on the snow cover and then on the water resources, aquatic chemistry, animal populations and vegetation that are influenced by snow