Arctic Snow Melt Hydrology: Observations, Modeling and Implications to Runoff Chemistry

During the last few decades considerable progress has been made in our understanding of the physical processes controlling snowcover formation, melt, and runoff. This work provides the basis required for a better understanding of, and ability to predict, the complex role snow plays in alpine and northern environments, including, for example, streamflow, surface-atmosphere interactions, and the fluxes of contaminants through the snowpack. The interaction of meltwater with strata within the snow, the resulting formation of preferential flow fingers, and re-freezing of meltwater as ice layers and ice columns within the snow, complicates our ability to model both the release of meltwater and contaminants from the snow. This paper will provide a synthesis of the current state of our understanding of, and ability to model, snow melt and snow melt runoff. A major focus will be to review progress to date on the importance of the heterogeneous nature of the snowcover over a wide range of scales, and implications to contaminant runoff.