Spatial and temporal trends of snow cover properties in a large subarctic basin: implications for basin-wide, end-of-winter snow water equivalent estimates

Basin-wide snow water equivalent (SWE) is an important hydrologic variable. For large basins, SWE is often estimated using a sparse network of sites. In this study, historical snow surveys (1978-2017) conducted across the 13,700 km2 Snare River basin near Yellowknife, NWT, were analyzed to identify local and regional scales of variability as well as temporal trends. Two field seasons of enhanced surveys (2016/17) were conducted. Snow regimes were found to differ significantly between sites north and south of treeline. No statistically significant temporal trends in SWE were detected but snow depth was found to be increasing while snow density was decreasing. Surveys on lakes showed consistently lower SWE than in adjacent uplands by approximately 23%. North of treeline sites consistently contributed much greater error to basin-wide SWE estimates than sites to the south. The consistent regional differences were used to inform sampling strategies for each region.