ORIGIN AND BEHAVIOR OF THE 1938 CHOCOLATE CREEK DEBRIS FLOW FROM CHOCOLATE GLACIER, GLACIER PEAK VOLCANO, NORTH CASCADES, WASHINGTON
The flow is an example of an important hydrologic hazard at volcanoes in the Cascade Range. Two analogs that also resulted from long-term glacial recession are recognized: 1) The distal 1.6 km of Deming Glacier at Mount Baker collapsed in 1927, probably triggered by a local earthquake. 2) The distal 1.6 km of Kautz Glacier at Mount Rainier collapsed in 1947, triggered by intense rainfall. Both collapses yielded debris flows causing significant damage to transportation networks (highway and a railroad). Other glacial outburst floods at Cascade Range volcanoes are triggered by intervals of either hot weather or significant rainfall. Our continuing analysis of the Chocolate Glacier flow will determine its trigger, the processes of transformation both proximally to and distally from debris flow, and the characteristics of the glacier and its setting, with the goal of indicating what other glaciers at Cascade Range volcanoes could be at risk of collapse in the future.