An integrated modelling approach to understanding subglacial hydraulic release events

Outbursts of subglacial water from numerous alpine glaciers have been observed and documented. Such events tend to occur ill spring and are thus attributed to nn inability of the winter subglacial drainage system (characterized by high water pressure and low capacity) to accommodate a sudden and profuse influx of surface meltwater. Prior to a release event, bursts of glacier motion are common, and the release then precipitates the restoration of summer plumbing that damps or terminates surface acceleration. The. events bear witness to the importance of interactions between surface melt, runoff englacial water storage and internal routing, in addition to subglacial drainage morphology. Using a distributed numerical model to simultaneously solve surficial, englacial and sub-glacial water-transport equations, we investigate the role of these components in a hydromechanical event observed at Trapridge Glacier, Yukon Territory, Canada, in July 1990.