Glacial lake outburst flood
A sudden flood caused by the failure of a natural dam holding back a glacier-fed lake. It can release large volumes of water and sediment downstream.
Moraine-dammed lake: A lake held back by unconsolidated sediment deposited at a glacier’s edge. Its loose sediment dam can be breached or eroded by rising lake water.
Lake Missoula floods: Catastrophic Ice Age floods released when an ice dam blocking glacial Lake Missoula failed. Repeated ice-dam failures produced an exceptionally large sequence of outburst floods.
Glacial lake inventory: A systematic record of glacial lakes, often mapped from satellite imagery. Inventories identify lakes that may grow or threaten settlements and infrastructure.
Flash flood: A rapid flood that develops soon after intense rainfall, dam failure, or another sudden water release. A glacial lake outburst flood is a high-energy, dam-failure-driven form of rapid flooding.
Glacier retreat: The long-term reduction in a glacier’s extent or mass, commonly caused by sustained negative mass balance. Retreat can expose depressions where new lakes form and existing lakes expand.
Ice-dammed lake: A lake impounded by glacier ice that blocks a valley or drainage route. A change in the ice barrier can suddenly release the lake.
Lituya Bay megatsunami: A 1958 tsunami in Alaska’s Lituya Bay generated by a rockslide into the bay. It is sometimes confused with an outburst flood, but its trigger was a landslide.
Glacial lake hazard assessment: An evaluation of the likelihood and potential impacts of glacial lake outburst floods. Assessments prioritize lakes for monitoring, engineering, and emergency planning.
Floodplain: Low-lying land beside a river that is periodically inundated by floodwater. Floodplains downstream can be inundated by outburst waves and deposited sediment.
Climate change and glaciers: The effects of changing climate on glacier mass, extent, and behavior. Warming changes lake formation and glacier conditions, but local flood risk does not respond uniformly.