Snowfall into a forest and clearing

Experiments in February–March 1987 at Fraser Experimental Forest in Colorado, U.S.A., compared the number flux of snow particles above the center of an 80-m wide clearing with simultaneous samples in and above the forest 85 m upwind. Numbers of snow particles counted with electronic sensors on towers decreased with decreasing height below the canopy top in the forest and also nearer the surface in the clearing. Average fluxes were greater in the clearing than in the forest, and these differences increased with increasing average wind speed, in the 0–6 m s −1 range, measured during the experiments. The greater flux at the tower in the clearing could not be completely explained by interception of snow in the forest canopy, indicating that aerodynamics may have played a part in creating the difference, even in those light winds. A plumer or concentration of snow particles appeared to have developed near the top of the canopy and spread into the clearing.