Snow depth variability in a small alpine watershed

The effects of mountainous topography and wind result in widely variable snow depths in alpine basins. High variance among measured snow depths and limited accessibility in alpine watersheds complicates estimation of snowpack water equivalent (SWE). Snow surveys at eight snowcourses were used in a water balance calculation for 1994 in the Andrews Creek Basin {drainage area of 183 hectares), Colorado. A mean snow depth from a single snowcourse in a forested area was compared to mean depths at seven additional snowcourses representing a variety of terrain around the watershed. The mean snow depth from the single snowcourse differed statistically from the other mean depths and underestimated the average snow depth, estimated by all eight snowcourses, by 1.2 meters. A water-balance calculation (comparing annual precipitation to measured runoff) indicated an estimated mean snow depth for the basin was substantially better when based on several snowcourses covering a range of conditions, rather than based on only one snowcourse.