Observations of the 2021 Muldrow Glacier Surge in Denali National Park
 

Geophysics Dept./GI UAF

Throughout the world, approximately one percent of glaciers are known to exhibit surge-type behavior. In general, these systems are distinct from non-surging glaciers which have relatively consistent velocities through time. Surging glaciers, in contrast, are known to exhibit prolonged (years to decades) quiescent phases during which the rate of ice mass transport can be multiple orders of magnitude slower than during the short-lived surge. The dynamics of glacier surges have been previously observed and described in multiple settings throughout Alaska, however many open questions regarding surge behavior remain. The recent surge of the Muldrow Glacier in Denali National Park provided an incredible opportunity to collect novel datasets with the goal of better understanding surge behavior. After the surge began in early 2021, an extensive campaign was launched by researchers from the National Park Service and the University of Alaska Fairbanks to record this rare event. Only two previous surges of the Muldrow Glacier are known in the written record, one in 1956-57 and the other in the early 1900s. Surface velocities of the glacier were recorded with satellite imagery, on glacier GPS, and a ground based interferometric radar. Multiple aerial surveys utilizing structure from motion photogrammetry provide high resolution digital elevation models throughout the surge allowing for estimates of ice flux. Time lapse photography, an array of seismometers, and stream gauges deployed along the margins of the glacier may provide insight to the subglacial hydrology driving the surge event. Taken together, these datasets offer one of the most complete views to date of a glacier surge and have the potential to significantly improve our understanding of these events.