Computer programmers stop snow in its tracks

Selecting the site of avalanche barriers has become a science Keystone Archive

Computer scientists in Geneva have developed a new programme which helps to determine the most effective places for avalanche barriers. The system works by predicting how snow is carried by the wind and how it is deposited.

The programme has already helped the authorities in canton Valais determine the best locations for avalanche fences near Verbier.

Until now, the siting of such barriers has been largely hit and miss, says Dr Alexandre Masselot, who spent five years at Geneva University’s computer science department, working on the project.

“You can ask a human expert where to put a fence and then wait a couple of winters after snow has fallen to see if it is doing the most effective job and then move it a bit. That costs a lot of money and takes a long time.

“In the case of Verbier, we copied the terrain in three-dimensions and simulated the effects of the wind and tried different positions of the fences.”

Scientists trying to model the movement air or liquid often use equation-based solutions. Instead the Geneva team imagined the snow as small particles which interacted according to simple rules. They were then able to observe complex phenomena like windslabs, snowdrifts and cornices.

Another novelty was the linking of dozens of computers together to run the programme – a technique which has proved much cheaper and more effective than using the fastest computer currently on the market.

Despite the benefits, Dr Masselot warned that the new programme doesn’t solve all the problems of erecting new fences to protect against avalanches. He said it was just one more tool in the armoury.

by Vincent Landon