Snow Accumulation and Ablation
on Boards of Different Sizes and Shapes
Rolf Pfister1 and Martin Schneebeli1
Snow accumulation and ablation on trees play a major role for the structure of the snow cover in
snow hydrology and for protective effects of boreal and subalpine forests against avalanches. To
better estimate this impact we examined the processes of snow accumulation and ablation on boards
of different sizes and shapes. Boards were selected because real branches are too difficult to measure
and model the complicated processes of interception. For this purpose we exposed the boards to
natural and manmade snowfalls. After each snowfall, we measured the accumulated snow water
equivalent on the boards as well as different snow characteristics and meteorological conditions. To
investigate the ablation processes, we exposed the boards in an environmental chamber that allowed
us to control the temperature and the short- and longwave radiation.
The observed snow interception efficiency increased with board width for snowfalls at a mean air
temperature below 3C. This is explained by the decreasing rebound of the snow crystals near the
border. At temperatures above 3C the snow interception efficiency was independent of the board