Estimates of threshold windspeed from particle sizes in blowing snow

Abstract

Particle size distributions measured in the saltation layer of drifting snow are fitted reasonably well by the two-parameter gamma function. Using these data, the mean particle size 0.25 m above the surface is predicted as a function of windspeed, from the theoretical relationship developed by Budd (1966). Average particle diameters, measured with a photoelectric snow particle counter at a site in southeastern Wyoming, U.S.A., during drifting of moderate intensity, are larger than mean sizes predicted by theory. These experiments provide empirical equations that allow threshold windspeeds for snow transport to be estimated by monitoring an anemometer and particle counter.