Global and Synoptic-Scale Forcings on Extreme Snow Melt Runoff Events

The role of the atmosphere, both synoptically and on larger scales, in rapid snowmelt episodes has been the subject of previous research. When considering relationships between global scale forcings, snow ablation and stream flow, analysis performed on drainage basins over the western United States suggests that an advance in timing of peak spring season discharge has occurred over the past fifty years.  In some instances, rapid ablation events take place under diverse air mass or synoptic conditions and each air mass condition may be associated with distinct surface energy fluxes responsible for ablation.

Motivated by recent trends in Northern Hemisphere spring snow cover, this study seeks to quantify the global and synoptic-scale forcings associated with rapid snowmelt events, with particular attention to the role of major atmospheric and oceanic teleconnections. Using a climatology of extreme ablation events for the Chesapeake watershed from 1960-2009, the relationship between daily snow depth change, stream flow, synoptic-scale air mass types and low frequency modes of atmospheric variability are explored.