Avalanches

An avalanche is a moving mass of snow or snow and ice. A large avalanche can mobilise many thousands of tonnes of debris, easily enough to destroy buildings, forests and other infrastructure such as ski lift pylons. Along with falls they are one of the principal dangers faced by backcountry travellers.

Avalanches can be divided into three main categories:

1. Slab Avalanches
2. Loose Snow Avalanches
3. Wet Snow Avalanches
4. Weak Layers

Avalanches are far from a random event. Most backcountry avalanche accidents are triggered by the victim or a member of the victim’s party with slab avalanches the main danger, especially during the winter months of January to March in France.

Avalanches occur when the frictional bonds between a surface layer and the underlying bed and surrounding snow are overloaded. Possible triggers are a skier, snowboarder or an outside event such as a falling ice-block or meltwater percolating through the snow pack.

We have a review of the current avalanche gear and snow safety resources including avalanche training, books and equipment.

Contents

• Introduction
• Avalanche Bulletin
• Search and Rescue
• Avalanche Avoidance
• Risk Reduction Methods
• Glossary
• Accident Statistics

Further Information

• http://www.avalanches.fr/ - CEMAGREF and French Environment Agency web site
• http://www.anena.org - Association Nationale pour l'Etude de la Neige et des Avalanches
• http://www.henrysavalanchetalk.com - Avalanche Talks and on snow safety training