Geometry and Density of Drifts Formed by Snow Fences

This paper presents results from studies of snow-drifts formed by vertical-slat “Canadian” and horizontal-slat “Wyoming” snow fences having 50% porosity and heights H from 0.8 to 3.8 m, on nearly level terrain. Characteristics of equilibrium lee drifts behind the Wyoming fence include cross-sectional area 19.3 H 2 , length 30 H , maximum depth 1.20 H . and water-equivalent volume 6.8 H 2.18 . Up-wind drift dimensions include maximum depth 0.5 H and length 12 H . Drifts behind Canadian fences are about 25% smaller than for the Wyoming design. Polynomial regression equations are fitted to drift profiles for both fence types. Relationships are presented for the effects of wind orientation and curvature of drifts near fence ends, as well as empirical equations describing pre-equilibrium geometry relative to degree of saturation. Mean density ρ (kg/m 3 ) of drifted snow having depth y (m), is given by ρ = 376+158 log y .