Snow in the McMurdo Dry Valleys is a potential source of moisture for subnivian soils in a cold desert ecosystem. In a water-limited environment, enhanced soil moisture is expected to provide more favourable conditions for subnivian soil communities. In addition, snow cover insulates the underlying soil from air temperature extremes. Quantifying the spatial and temporal patterns of seasonal snow accumulation and ablation is necessary to understand these dynamics. Repeat high-resolution imagery acquired for the 2009–2010 austral summer was used to map the seasonal distribution of snow across Taylor and Wright valleys, Southern Victorialand, Antarctica. An edge detection algorithm was used to perform an object-based classification of snow-covered area. Coupled with topographic parameters obtained from a 30-m digital elevation model, unique distribution patterns were characterized for five regions within the neighbouring valleys. Time lapses of snow distribution in each region provide insight into spatially variable aerial ablation rates (change in area of landscape covered by snow) across the region. A strong coastal to interior gradient of decreasing snow-covered area was evident for both Taylor and Wright valleys. The surrounding regions of Lake Fryxell, Lake Hoare, Lake Bonney, Lake Brownworth, and Lake Vanda exhibited losses of snow-covered area of 9.61 km2 (−93%), 1.63 km2 (−72%), 1.07 km2 (−97%), 2.60 km2 (−82%), and 0.25 km2 (−96%), respectively, as measured from peak accumulation in October to mid-January. Differences in aerial ablation rates within and across local regions suggest that both topographic variation and regional microclimates influence the ablation of seasonal snow cover. Copyright © 2012 John Wiley & Sons, Ltd.