DISTRIBUTION OF MAXIMUM ANNUAL WATER EQUIVALENT OF SNOW ON THE GROUND

Abstract

For later development of design snow loads, the water equivalent of snow on the ground appears to be the best meteorological variable for determining design values. The appropriate climatological series for this is the winter season maximum accumulated water equivalent series. Among many distributions investigated, the lognormal distribution provided the best fit to these climatological series. Distributions fitted to 140 stations provided data for preparing contour maps of the parameter estimates. In southern areas of the United States, where snow does not occur every year, the climatological series is a mixture of zeros and water equivalent, maxima. This requires the fitting of mixed distributions in these areas. A contour map is provided of the mixture parameter estimate. Methods for determining confidence intervals for quantiles from both distributions are developed.