Snowpack stratigraphy evolution at forested and open sites

Field observations of seasonal snowpack stratigraphy evolution over the course of a winter are described at open and deciduous forest sites. The predominant stratigraphic features of the two sites were similar, although the snow sometimes had dramatically different behavior in response to tree- and slope-induced local meteorological differences. Differences in solar radiation between the two sites produced differences in early snowcover, which then controlled the formation and nature of the basal ice layer that remained throughout the season. At this location, the greater longwave radiation induced by the trees at the forested, south-facing hill slope offset the greater solar radiation at the open site, so that the net allwave radiation at the two sites was approximately equal. More snowpack mass was lost during snowmelt at the forested hill slope than at the open site because the melt generated in the upper half of the pack flowed laterally through the pack in the down slope direction. At the open site, snowmelt at the surface flowed vertically through the pack, sometimes adding mass to lower layers. In addition, field observations illustrate that capillary effects produce observable changes in snowpack layering, and need to be included in modeling of metamorphic snowmelt processes.