Abstract

A single week-long warm event in midwinter in Svalbard flooded an inefficient en- and subglacial drainage system and led to a 2.5x velocity increase that remained in effect for the remainder of the winter - more than 3 months. Because of the long winter season, changes in winter velocity have a large impact on the annual average velocity. As the climate warms and surface melt and rain events increase during winter months, sustained high winter glacier velocities are likely to occur more often. Increasing glacier velocity near the terminus leads to additional ice entering the fjord, and an increase of ice dynamics contribution to sea level rise during winter.