Snow Depth Required to Mask the Underlying Surface

Abstract

The mean daily albedo of snow cover over sod, alfalfa, and bare soil was obtained over the course of 19 winters. This period provided a wide range of snow depths (up to 61 cm), albedos (a maximum of 95%), and densities (from less than 40 to more than 350 kg m-3). The mean over-winter height of the sod was 4 to 6 cm, while the alfalfa ranged from 7 to 15 cm tall. It was found that the rate of increase of the albedo with increasing snow depth showed a marked decrease once the albedo reached about 70%. It was also found that the standard deviation of the albedos decreased appreciably once the albedo reached 70%. Accepting an albedo of 70% as indicating the depth sufficient to effectively mask the underlying surface, 5, 7.5, and 15 cm of snow over the bare soil, sod, and alfalfa were required, respectively, for the three surfaces.