Partitioning the deposition of winter snowfall as a function of aspect on forested sites

Snowpack accumulation, expressed as Peak Water Equivalent (PWE) is usually least and peaks earliest on south facing slopes. This study, conducted as part of an ongoing effort to define snow deposition and ablation processes, attempted to partition the components in the deposition process that could result in the differences in PWE. Total flux into the canopy on opposing north and south facing slopes was found to be similar, although some difference in particle size at interior canopy positions occurred. Ventilation, or windspeed within the canopy, was greater on the south slope. Throughfall (storm basis) was equal on both slopes but accumulation on the south slope lagged behind that on the north slope. The initial lag was attributed to evaporative differences. In March, melt on the south slope was more significant. The south slope had 7.7 cm less water equivalent than the north slope on April 1. One third of the difference was attributed to melt, two thirds to greater vaporization.