Snow-Collection Mechanisms and the Capacities of Snow Fences

Abstract

The shapes of equilibrium lee drifts formed by snow fences are scaled in proportion to height of snow fences independent of the snow and weather conditions, even in small-scale models, but those of up-wind drifts are not.Field studies have been made of the snow-collection mechanisms of a snow fence. It has been observed that particles of saltated snow piled up to windward, and that it was the previously suspended particles that were heaped up in the lee drift. It can be shown that the shapes of up-wind drifts vary in different snow and weather conditions because threshold shear stress and drift-snow saltation depend on the physical properties of the surface snow.Equilibrium lee drifts are scaled in proportion to fence height, because snow and weather conditions have less effect on threshold wind speed for suspension, and the sheltering effect of a fence is scaled in proportion to the height of the fence.The dimensions of the equilibrium drifts at snow fences were measured, and maximum snow-retention capacity and lee-drift length presented as a function of fence height, fence density, and depth of snow cover.