Glacial lake outburst flood (GLOF)

During a period of glacier recession, back from a terminal moraine, a lake may form. This lake is impounded by an unstable pile of debris and buried ice. Catastrophic failure of the moraine will result in a devastating flood. Usually associated with high mountain regions such as the Andes and Himalaya.

Evidence of a glacial lake outburst flood in 1977 at Nare Glacier, in the Khumbu Himal, Nepal, illustrating severe erosion of old moraines downstream. The terrace on which the village of Pangboche is located has also been partially destabilised. Photo M. J. Hambrey, 2004.