Avalanche

Geography glossary

Also called: Snow avalanche · Topic: Natural Hazards and Disaster Management in India · NCERT: Class 6, Ch 3 "Landforms and Life"; Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"

Meaning

An avalanche is a sudden fall of a large mass of snow down a steep mountain slope. It can be triggered by:

  • Heavy snowfall in a short spell on top of weak snow layers.
  • Sudden warming.
  • Wind piling up snow.
  • Earthquakes.
  • Skiing or construction work.

NCERT counts avalanches as a terrestrial hazard. They block roads, bury villages and put soldiers and travellers in danger. In India, DGRE (formerly SASE) issues avalanche warnings.

Example

Avalanches often hit Siachen, Zojila and Gurez in Jammu and Kashmir and Ladakh. Other prone areas are Lahaul-Spiti and Kinnaur in Himachal Pradesh, Uttarakhand and Sikkim.

Don't confuse with

  • Landslide: a mass of rock and soil, not snow, sliding downhill.
  • Glacial lake outburst flood (GLOF): a flood of water from a burst glacial lake. An avalanche can trigger a GLOF, but an avalanche is moving snow, not floodwater.

Related concepts

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