A characteristic “mares' tail” pattern of falling snow (observed in vertical section by radar) suggests that the snow is generated continuously, in compact generating elements; the pattern results from the snow's falling at constant velocity through the wind shear. For constant wind shear, the snow trails are parabolic, and before reaching the ground become almost horizontal. The velocity of the pattern is that of the generating elements, and can be compared with wind strengths aloft to locate the height of the generating elements when these elements are not detected by the radar. Abstract A characteristic “mares' tail” pattern of falling snow (observed in vertical section by radar) suggests that the snow is generated continuously, in compact generating elements; the pattern results from the snow's falling at constant velocity through the wind shear. For constant wind shear, the snow trails are parabolic, and before reaching the ground become almost horizontal. The velocity of the pattern is that of the generating elements, and can be compared with wind strengths aloft to locate the height of the generating elements when these elements are not detected by the radar.