Glacial Hazards in Glacier National Park, Montana

The spatial and temporal aspects of glacial hazards in the Lewis and Livington Ranges of Glacier National Park, Montana are examined. Ice avalanches have historically been a hazard in the Park, and continue to be so from glaciers in cirques. Ice avalanches were more common and more widely distributed during and immediately after the Little Ice Age. As glaciers and the threat of ice avalanching have receded in the twentieth century, the potential for debris flows from moraine-dammed lakes has risen. Glacial calving, slope instability, rapid snowmelt, and intense thunderstorms provide potential triggers for debris flows in the Park, some of which could produce catastrophic maximum discharges. [Key words: Glacial hazards, ice avalanche, debris flow, Glacier National Park, Montana.]