The seasonal snowcover and snowmelt (2008–2010) of an extensive low-gradient wetland at Polar Bear Pass, Bathurst Island, Nunavut, Canada (75°40′ N, 98°30′ W) was examined. This wildlife sanctuary is characterized by two large lakes and numerous tundra ponds, and is bordered by rolling hills with incised hillslope stream valleys. In arctic environments snow remains one of the most important sources of water for wetlands. End-of-winter snowcover measurements (snow depth, density, water equivalent) together with direct and modeled estimates of snowmelt provided an assessment of the seasonal snowcover regime of representative terrain types comprising upland (plateau, stream valley, late-lying snowbed) and lowland landscapes (wet meadow, ponds, lakes). In all three seasons, deep and persistent snowpacks occurred in sheltered areas (stream valleys) and in the lee of slopes adjacent to the wetland. Exposed areas yielded shallow snowpacks (e.g. plateau, pond) and they melted out rapidly in response to favorable weather conditions. Overall, the basin snowcover and melt progression was dominated by accumulation and melt occurring in upland areas. We surmise the sustainability of this low-gradient wetland is dependent on snowmelt contributions from upland sites.

Supplementary data