Glacial Lake Outburst Floods

A glacial lake outburst flood, commonly abbreviated GLOF, occurs when a lake formed by retreating glacier ice — often dammed by an unstable ridge of loose glacial debris called a moraine, or by ice itself — breaches suddenly, releasing a massive pulse of water and sediment down the valley below. As glaciers retreat worldwide under warming temperatures, more and larger such lakes have formed, particularly in the high mountain ranges of the Andes and the Hindu Kush Himalaya, both because moraine dams are structurally weak compared to bedrock and because triggers such as ice or rock avalanches falling into the lake, or intense rainfall, can overtop or rupture the dam within minutes.