An outline of the thermodynamics of snow melt

The heat required to raise the temperature of dry snow is shown to be very small compared to the heat required to convert the snow entirely to liquid water. The various factors involved in the heat transfer processes leading to the melting of a snow cover are explained separately. The solar radiation absorbed may be balanced by irradiation from the snow surface. heat transfer by conduction through the snow to the earth or to the atmosphere is negligible. Heat exchange by convection and condensation exceeds heat transfer by any other means. Evaporation and warm rainwater also are contributing factors. The liquid water content and the density of the snow cover, the melting of frozen ground, the areal distribution of the snow cover, and the air trajectory over the snow must be considered in evaluating the heat transfer processes or forecasting snow melt. A method of estimating the rage and progress of snow melt is applied to a specific example. Formula development and application are included.