Prediction of Snow Avalanches by Using Surface Layer Heat Fluxes

Abstract

Snow avalanches are formed in the mountainous snow regions mostly due to the presence of weak layers between the adjacent snow layers. Since the prevailing at mosphere in these regions is stable, weak snow layers are formed due to the presence of surface hoars, which is measured by surface layer heat flu xes. Surface hoar forms when relatively mo ist air over a cold snow surface beco mes over saturated with respect to the snow surface; causing a flu x of water vapor, which condenses on the surface, and creates feathery crystals (the icy layer equivalent to dew). Once buried, the resulting weak layer is a serious consideration for avalanche format ion. Surface hoar tends to form at night when the snow surface generally cools and the adjacent air becomes over saturated. The surface layer heat flu xes in the atmospheric boundary layer over Himalayan regions are calculated here by stability criteria using the bulk aerodynamic method.