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?

beacon search

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.

How common are Multiple Burials? Avalanche Incidents in Tyrol, Austria. 1997-2003. The Avalanche Review vol 26, no 2. Dec 2007

Posted by davidof on Sunday, 02 March, 2008 at 12:17 AM

I totally agree with you Davidof: there is really no logic in leaving out the cases where persons involved didn’t have transceivers. With reasoning (and statistics) like this it would also be possible to argue that transceivers don’t make a difference, since many avalanchevictims didn’t have one and therefore transceivers didn’t make a difference....

Bull@&%* !

Posted by Rolf on  Monday, 10 March, 2008  at 04:01 PM

I have a new transceiver with the multiple victim feature and just completed an avalanche training certification. In the certification course we did simple comparisons of all the transceivers, from the simplest to the “latest and greatest”. All of them appeared to transmit about the same signal strength. My transceiver appeared to have the greatest receiving range on a buried transceiver.

I agree that at this time, few back country skiers carry transceivers. However, here in California I would estimate that most mountaineering skiers (alpine touring) do carry transceivers. There is a lot higher interest in transceivers now than in the last 30 years I’ve been skiing the back country. Two of my friends and I purchased transceivers in the past year and we’ve all skied in back country and mountaineering for at least 20 years.
There’s also a lot more backcountry and mountain ski travel in the US than 20 years ago. Therefore I believe that the need for multiple victim search will increase and that historical statistics may not give a good picture of the future.
Of course the best outcome is for better avalanche forecasts, education, awareness and most importantly more “smarts” in how we ski so we don’t get caught.

Seven of us performed a practice search for two buried transceivers last week in perfect conditions. We found the first “victim” in about 3 minutes. Then 5 of us looked for the second victim. With confusing signals, we went in two directions. I then took my transceiver to the found victim and marked it. My transceiver immediately pointed to the second victim, 40 meters away in a third direction and I led the other searchers there. Total time to dig out both “victims” was 12 minutes. Marking out the first “victim” made a huge difference in efficiency for the second one.

For the record, mine is the Mammut Barryvox Pulse.

Posted by  on  Tuesday, 18 March, 2008  at 11:23 PM

Manuel Genswein, an avalanche educator has hit back at the BCA study. He shares our worries about the figures accusing the BCA team of “statistical tricks”. Genswein also tackles the questions of signal overlap and “marking” saying that modern digital beacons are actually very good at solving the majority of easy multi-burial scenarios and coupled with an analogue function (not available on the BCA Tracker beacons) an advanced or pro user can solve all scenarios. He shares Fred’s view above that “marking” is an extremely powerful technique, essentially reducing a multi-victim search to a series of single victim searches.

It is a robust response and we will be keeping an eye on developments.

-- The Avalanche Review p 8-9. Apr 2008

<h3>Further Information</h3>

Posted by davidof on  Thursday, 10 April, 2008  at 12:23 AM

Hi Davidof,

Unfortunately I can’t find Genswein’s response under the link you’re refering to. Is it me, or is the link maybe incorrect? I just spent 4 days training with Genswein during a congres on avalanche rescue, so I am very curious what he has to say on this (though I have a vague idea)!

Posted by Rolf on  Tuesday, 22 April, 2008  at 03:16 PM
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