Multiple Avalanche Burials, rarer than you think?
There is a great deal of focus by amateur backcountry enthusiasts on multiple burial avalanche accidents. It is a major factor in avalanche beacon choice with transceivers such as the Pieps DSP, Ortovox S1 and Barryvox Pulse simplifying the whole process with easy to read graphical displays. But should skiers and boarders be losing so much sleep over the multiple burial scenario?
Some experts think not. Backcountry Access who make the Tracker and Nic-Impex who manufacture the ARVA range have both told us that amateurs should focus on being able to rescue a single victim as quickly as possible. Pieps have just introduced the Freeride beacon, a cut down but affordable model with exactly this aim.
New research by Dieter Stopper, a UIAGM guide and former research director of the German Alpine Club and Jon Mullen, a consulting engineer from Boulder, Co suggests they are right. As the co-inventor of the Three Circle Method, a protocol for finding multiple avalanche victims, Stopper admits he has been partly responsible for pushing multi-victim searches into the forefront of educational efforts.
The research defines a multi-victim scenario as one where special techniques are required to distinguish between different victims. This generally means that both victims are completely buried within the search range of a beacon thus creating a “flux-line” soup and therefore requiring special techniques to isolate signals. For the purposes of their analysis victims had to be wearing beacons. They also make the point that there must be two rescuers. If there is only one searcher then the protocol is to locate the first (closest) victim and dig them out, turning their beacon off in the process.
The authors evaluated data from 432 avalanches in the Austrian Tyrol between 1997 and 2003. Of these 256 were human related and in 188 people were buried. Of the 188 incidents a beacon search was unnecessary as part of the victim was visible on the surface. In just 68 of the incidents a human was completely buried. However in 37 of these incidents either the victim or rescuer didn’t have a beacon. Therefore in just 16.5% of incidents was a beacon search possible and necessary. There were just 8 multiple burial situations. In six of these incidents standard single beacon protocols were all that was necessary to locate victims. They conclude that a special case multiple burial situations are extremely rare, less than 1%.
However there are a couple of points. The research was sponsored by BCA who obviously have some interest in down playing multiple burial scenarios. We also wonder about the statistical basis and whether just avalanches involving people should have been considered. We were also dubious about excluding all burials where the victims were not wearing transceivers. Three of the multiple burial cases excluded (Cases 3, 4 and 5 in the study) were only discounted because the searchers didn’t use special search strategies… but they could have done. Still even given these question marks true multiple burial scenarios are probably around 3-5% of total incidents involving backcountry travellers. The study makes the point that educators would do better to focus on single search, rescue organization and shovelling techniques as well as avalanche avoidance.
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