Avalanche

An avalanche is a mass of snow and ice falling suddenly down a mountain slope and often taking with it earth, rocks and rubble of every description (WMO, 1992).

Thousands of avalanches occur every year, killing an average of 500 people worldwide. Avalanches occur when massive slabs of snow break loose from a mountainside and shatter like broken glass as they race downhill. These moving masses can reach speeds of 130 km/hour within about five seconds. They cannot always be predicted but the weather conditions, which make them more likely, can be forecast in advance. Most accidents now occur because people ignore warnings. The majority of avalanche incidents are due to slab avalanches with skiers involved. Avalanches are bigger, travel greater distances and are triggered earlier in the year. These changes can be attributed clearly to rising temperatures, which have reached 0.2 to 0.4 degrees annually in some parts of the Himalayas.

Avalanche protection and control measures include early warning which is key (EAWS). By way of controlled explosions, artificial avalanche triggering aims temporarily to safeguard possible starting zones (SLF). Defensive structures prevent the formation of avalanches. In order circumstances, when an avalanche is released, it can be diverted or intercepted by a dam. Other means of protection against avalanches include physical structures for buildings and snow sheds (SLF).

Avalanche risk factors

  • Quick changes in weather, snowpack and terrain.
  • Increasing human populations: winter sports lovers at ski resorts and developers building in vulnerable locations.
  • Climate change.

Vulnerable areas

  • Human settlements in avalanche-prone zones.
  • Rural mountainous villages with no early warning systems.
  • Human settlements with no forest cover.
  • Skiing populations and tourists not educated in avalanche risk.

Risk reduction measures

  • Not constructing buildings, roads, etc. in avalanche hazard areas.
  • Early warning systems at local and national levels.
  • Information on avalanches, their impacts and risks for tourism information offices.
  • Tree planting to protect against the release of avalanches.
  • Building codes and appropriate materials to reinforce resilience.
  • Raising awareness, educating and training residents and visitors on what to do before, during and after an avalanche.

Latest Avalanche additions in the Knowledge Base

Research briefs

Communities in Nepal expand to risk areas, despite hazards

A recently published study finds that more than a quarter of the new houses in Pokhara, the second-largest city in Nepal, are being built in highly dangerous areas susceptible to multiple natural hazards.
Glacier Hub
Documents and publications

Assessing the interaction between mountain forests and snow avalanches at Nevados de Chillán, Chile and its implications for ecosystem-based disaster risk reduction

Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk to mountain communities around the world. In particular, where documentary records about these processes are rare, decisions on

Update

Peering beneath the powder: Using radar to understand avalanches

New research using high-resolution radar images from Switzerland’s experimental test site shows that snow temperature is a key factor in classifying avalanche behaviour. The data demonstrate the limits of current avalanche propagation models, which are typically based upon the basic distinction between dense and powder avalanches.
Eos - AGU
Research briefs

Global warming increases the risk of avalanches

The impacts of global warming are felt especially in mountainous regions, where the rise in temperatures is above average, affecting both glacierized landscapes and water resources. The repercussions of these changes are manifold and varied, from retreating glaciers to an increase in the frequency and intensity of snow avalanches.
University of Geneva
Update

Meet the villagers in Tajikistan who are putting disaster risk knowledge into practice

In central Tajikistan’s Rasht Valley the NGOs Mercy Corps and Welthungerhilfe have been providing awareness training on the risks the communities face, and how they can minimise them. The villagers are now applying this newly gained knowledge in their day to day life.
European Commission
Update

SFU avalanche expert uses GPS to make winter backcountry travel safer in Western Canada

A new study strives to make the mountains safer for backcountry enthusiasts. The research team equips experienced commercial backcountry guides in Western Canada with GPS devices to capture their operational knowledge and develop tools that preserve and use this knowledge as well as help train future guides.
Simon Fraser University
Update

Chandigarh-based research organisation developing technology for real-time avalanche monitoring

The Chandigarh-based Snow and Avalanche Study Establishment (SASE) is developing technology that will provide real-time prediction before an avalanche is triggered. The Wireless Sensor Technology (WST) will gather information from remote locations, which will ensure uninterrupted data streaming to base station on a near realtime basis.
Live-Mint/Hindustan Times, HT Media Limited
Update

Can computers forecast avalanches better than humans digging holes?

In the world of avalanche forecasting, manual methods are state of the art. But meteorologists are honing a computer model to simulate the snowpack. This could prove particularly useful in remote areas where there are no avalanche professionals to collect snowpack information.
New York University
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