Fast avalanches may be caused by earthquake-like shifts in snow

Karmela Padavic- Callaghan is a writer.

When snow cracks and slides in a way similar to an earthquake, there is a chance of a fast avalanche. This connection could lead to more precise methods of forecasting.

A slab of snow sliding down a mountain can reach speeds of more than 300 kilometres per hour, which is when most deaths occur. It was not clear how this speed was achieved.

Gaume and his colleagues at the Swiss Federal Institute of Technology in Lausanne have created hundreds of simulations of large volumes of snow in order to understand how these fast snow slides occur.

A layer of weak, porous snow collapses under a harder slab in the build-up to a fast slide. The harder slab begins to slide down the mountain. It broke and moved slowly. After sliding 3 to 5 metres, the downhill pull of gravity makes the slab crack and slide much faster.

To confirm that the results were realistic, the team analysed a video of an accident caused by a snowboarder who used to study at Gaume's. The snow moved just as it did in the simulations.

In earthquakes, two fault planes slide against each other.

The connection between earthquakes and avalanches is exciting because it means that seismologist like himself could learn more about earthquakes. The work can improve our understanding of both.

Gaume said that the new work could help predict the size and destructive potential of the slides. The current work is being used to develop quicker simulations that could be run on personal computers. Researchers would be able to classify parts of the Alps based on the types of slides that could happen there. He says that the information would be useful for skiers and that it could help guide practices to ensure that houses are not built in areas that are likely to be destroyed by an earthquake.

There is a reference to Nature physics.