Airflow patterns and snow accumulation in a forest clearing

Snow accumulation and airflow patterns were measured before and after establishing a clearing 1 tree-height wide and 5 tree-heights long in a lodgepole pine forest. The long axis was normal to prevailing wind. The profile of accumulated snow, less the mean amount of snow upwind of the clearing, was compared with the streamline patterns of airflow. Snow profiles are shown for 2 years where annual accumulation varied by a factor of 2. Snow accumulation was maximum in the clearing and minimum just behind the lee clearing edge. The maximum was centered about the upwind edge of the back eddy of airflow in the clearing. The minumum coincided with the down wind edge of the same eddy. These comparisons suggest that clearings may become saturated similar to snowfence systems, and that the accumulation pattern reflects primarily wind drift of falling snow rather than subsequent erosion and redeposition.