Surviving An Avalanche

They are the number one fear of skiers - and for good reason. In Flipside 28 we explain what really causes an avalanche, and the terrible damage they can do. Here we add how authorities test avalanche behaviour, and a first hand survivor's story...

Attempting to predict when an avalanche is going to occur is of major concern to any country with mountains, especially those used for sports or with people living in close proximity. Understanding how, and why an avalanche occurs can help prevent lose of life.

Every year throughout the world, around 150 people are killed by avalanches but it only takes one big catastrophe to alter that figure massively, especially as more people are venturing further into the wilderness areas in search of more extreme skiing, boarding or climbing.

Here are some examples of death by snow: In Canada, 28 died during the 2002-3 winter season, in The United States there were 229 avalanche deaths between 1995 and 2002. In France, the winter of 2005- 6 was the deadliest since 1970. 55 people were killed in the five month period from December to April.

Avalanche studies are taken very seriously by the Swiss Federal Institute for Snow and Avalanche Research in Davos, Switzerland. The organisation has an avalanche testing site in the Sionne Valley in the heart of the Alps. The site has been built to study both an avalanche's behaviour and the forces it generates. This is done by artificially releasing avalanches to see what they do and by using computer simulation programs.

To study the impact, force and behaviour of an avalanche, a small wedge shaped, steel structure and a 20m high pylon are situated within the avalanche track. Within the steel wedge, there are transducers to measure force as well as sensors to measure pressure and strain. To gauge the behaviour and speed the researchers use radars, optical sensors and video analysis.

The site was chosen because it offers plenty of scope for releasing different types of avalanches. So successful was the first test carried out in 1999, the avalanche damaged the research centre and the pylon!

During the studies different shaped obstacles are put into the avalanche track with the measuring sensors placed within the steel wedge. The researchers observe from a separate shelter just opposite to the avalanche track this also includes some radar units. The test team are transferred to the shelter by helicopter with a landing platform on the roof to secure fast entrance to the shelter in case of increased avalanche danger.
 
Survivor's Story
Jerry Hill was part of a guided ski party on a circular tour, staying in huts overnight, lasting several days near the Swiss/Italian border in March this year. The weather was perfect, bright sunshine with a lot of new snow...

'We were about to go across the Monte Moro pass before a long ski down to Saas Fee. No-one had been across the pass for three or four weeks and the guide was a little cautious. Were about half way done and I was the last in the party. We were coming across the side of a slope at a height of around 2,500m.

'I suddenly felt my feet moving beneath me. I didn't hear anything but the others all turned around. Everything I knew about skiing flashed into my mind. But the stuff about skiing out of the way of the avalanche wasn't possible because I was coming across it sideways so it knocked my feet from underneath me.

'I fell forwards, face in the snow moving with the avalanche. I remembered I had to throw my ski poles away and swim, swim swim as much as you can to keep as much as possible up on the surface. I slide down about 150-200m but when it came to stop I was still on the surface and OK, although my heart was going a bit faster!

'The guide then kicked into action, muttering Italian expletives and ran back towards me, checked I was ok and gave me his skis to get into a safe area in case there is a second avalanche. I'd lost one ski and the guide searched for this with probes for about an hour but didn't find my ski or my poles.

'We still had about 90 minutes skiing to get down to our destination so the guide used my one ski right down to the bottom. I wasn't hurt but I was shaken and the next day, if we weren't on this circular route, I wouldn't have gone out but I had no option.

'We had done a lot of talking about avalanche situations and the group was very calm about what happened. We all had avalanche bleeps and had learned how to use them. Also we were all carrying shovels and probes and had done plenty of training before we had left. The guides are full of stories about people wearing bleeps that they have forgotten to turn on or have run out of batteries, so it proved to me just how important it is to be properly prepared. I'll definitely be going skiing again later this year but I will invest in one of the safety airbag systems before I go.'