Snow Drift

Wind-blown snow represents an age-old problem in the applied glaciology of most higher-latitude regions, but its physical intricacies first received attention in esoteric discussions on the long-term mass balance of polar ice sheets (Loewe, 1933, 1956). Measurements on the uniform unlimited surface of such ice sheets have shown good agreement, at least over a limited height range, with estimates for the concentration and flux of drift snow as a function of height and wind velocity based on turbulence theory. An alternative theory, developed concurrently from wind-tunnel results and field observations in Siberia, is discussed on the basis of its most recent exposition (Dyunin, 1974). Basic questions requiring further study include drift-snow concentrations at considerable heights, drift evaporation, and electrical phenomena. The main practical aspects of snow drift relate to the prevention of excess accumulation on roads, railway lines, and avalanche slopes; and to the encouragement of accumulation in fields and forests, and other locations where frost protection and/or storage of water is desired. The methods used are reviewed; they are beginning to rely on physical concepts and theories rather than solely on empirical formulae derived from engineering experiments.In regions of positive surface mass balance, buildings and other structures tend to become obliterated by snow drift. An important factor of this process is the fall-out of snow in the retarded flow on the windward side of the structure. Some recent attempts to measure and calculate that fall-out are discussed.