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Avalanche study pinpoints dangers

New insights about the process that triggers slab avalanches may be used to help predict potential snow hazards.

A slab avalanche begins, as seen from a distance.

Slab avalanches are often triggered by skiers and account for many skiing accidents.

House of cards

Scientists from the University's Centre for Materials Science and Engineering have proposed that the main cause of slab avalanches could be fractures under the surface.

These fractures, known as anticracks, cause a layer of snow to crumble inwardly like a house of cards.

Hidden dangers

It was previously thought that slab avalanches were caused by shear cracks, when a layer of snow slides off another.

Anticracks have been found to cause fractures over large distances. They can spread on gentle slopes and on the flat.

Our discoveries complete a piece of the puzzle of how avalanches occur. We hope this will help to pinpoint dangerous tell-tale signs and so avoid unnecessary dangers to people on mountains.

Joachim HeierliCentre for Materials Science and Engineering

The work, carried out with researchers at the University of Karlsruhe in Germany, was funded by the European Commission and is published in the journal Science.

Picture courtesy A. Duclos (www.data-avalanche.org)