Characteristics of snowmelt from NRCS SNOTEL (SNOwTELemetry) sites

Snowmelt is affected by a number of factors including elevation, slope, aspect, exposure, snowpack depth,surface reflectance and climatic or meteorologic variables such as solar radiation, temperature, wind speed, vaporpressure, and precipitation. Snowmelt models attempt to account for these factors in various degrees from simpleempirical relationships based on air temperature to detailed energy balance procedures. While detailed energybalance models should be superior in estimating snowmelt, there are rarely, if ever, adequate data sets available inpractice to use these methods without making simplifying assumptions. Unfortunately, these simplificationsusually reduce the models' ability to account for the various meteorologic factors that cause snowmelt to occur.Thus the models can produce estimates of snowmelt based on the input data available and the assumptionsrequired, but these estimates may not relate to actual snowmelt in timing or rate. Since actual snowmelt data isvery limited, it is seldom possible to compare model simulated melt rates with actual values. This paper issignificant because it presents an analysis of snowmelt data under a variety of conditions encountered atrepresentative SNOTEL sites selected from nearly 600 locations in the western United States. It thus provides arange of snowmelt information including average and maximum daily melt rates, time of onset and cessation ofmelt, and average day of maximum snowmelt that can be used to compare with snowmelt model simulations andother uses.