We’ve just been looking at December issue of Neige et Avalanches, the house magazine of the the French Snow and Avalanche Research Association (ANENA). As a major storm hits the French Alps and Pyrénées there is some information that should give pause for thought to any powder pigs thinking of ripping it up this week.
Regulars will remember that we took a look at off-piste accidents in general for last season. The ANENA compile a study of avalanche accidents from information supplied by the rescue services. This gives them access to some useful detail although it should be noted that this is not complete for all incidents.
Taking depth of burial, survival chances begin to drop rapidly for anyone buried more than 50cm and no-one survived who was buried more than 2 meters (8 deaths in total). The reasons are two-fold. The deeper a victim is buried the longer it takes to dig them out, a delay that can prove fatal due to suffocation or hypothermia. The weight of snow may simply crush the victim before there is any hope of rescue.
Looking at the burial time, 8 victims were recovered alive within the first crucial 15 minutes but after that survival chances decreased rapidly so that all 14 victims that were buried for more than 45 minutes were dead.
In France the rescue services take on average 45 minutes to arrive on the scene of an avalanche. Time for the alert to be given and a helicopter to be dispatched. If the weather is poor or the rescue services are already occupied with another incident the delay can be much longer. Last March the Chamonix Mountain Police (PGHM) had to send rescuers on foot to save a stricken climber, taking many hours to reach the scene. It is therefore essential that backcountry travellers are able to organise their own rescue attempt and are equipped with avalanche beacons, snow shovels and probes. This essential rescue equipment should not be an excuse to take unnecessary risks and safe travel procedures should still be followed.
Last season 8 of the 9 victims found by a probe search and four of the five victims found by avalanche rescue dogs were dead. A survival rate of just 13%. This figure rises to 42% (5 people) where the victim was wearing an avalanche beacon. As the ANENA reminds us, probably around 20% of avalanche victims are killed due to injuries received in the slide itself with maybe a further 10% suffocating shortly afterwards before any rescue can be organised.
In the same issue Jean-Christophe Braud describes an avalanche he survived. Crossing a small couloir consisting of fresh, wind transported snow deposited on a hard surface, conditions present today in the mountains, he felt like he’d taken a spin in a washing machine. He points out how important it is to remove rucksack waist straps and ski or snowboard leashes when crossing a suspect slope. If you don’t they will act like anchors dragging you under the slide. He was also surprised how quickly he was affected by cold, so make sure you are properly clothed and that zips and hoods are done up. It is also extremely important to protect airways if you are caught.
Perhaps his parting words are the most important: making a U-turn if the conditions are suspect never killed anybody.