LANDSLIDE LAKE OUTBURST FLOOD

LANDSLIDE LAKE OUTBURST FLOOD

Subject: Geography

Context : New evidence suggests that the incident may have been caused by a breach in a temporary pool or lake formed by obstructions due to landslides or snow avalanches — an event described as a Landslide Lake Outburst Flood (LLOF).

Concept:

• Glaciologists and geologists identified a steeply hanging bit of a glacier which likely developed a crack and caused a landslide, triggering an avalanche and the subsequent flooding.
• While landslide-triggered flows could cause enough heat to form temporary, transient dams of water that get quickly washed away in a flooding event, the event is not a ‘glacial outburst
• A landslide or snow avalanche can create obstructions in the normal path of a flowing river or stream, which results in the formation of a temporary pool, or a dam-like situation.
• When this obstruction finally gives way to the force of accumulating water, it creates a situation similar to a lake burst. This is called Landslide Lake Outburst Flood.
• In the case of an avalanche, snow adds to the volume of water.