Conventional wisdom says that if you are caught in an avalanche swim for your life to stay on the surface but according to avalanche expert Dale Atkins it is wisdom that may kill you. According to Dale the swimming technique was first described by a French survivor back in 1864 and has been oft repeated since. Before joining Swedish firm Recco as a consultant Dale spent for nearly twenty years as a senior avalanche forecaster at the Colorado Avalanche Information Center in Boulder and has done time as a ski patroller and rescue worker.
Dale agrees with the basic idea is that a human body is denser than snow but says that an avalanche is a granular flow not liquid and what matters is volume. Small particles settle on the bottom while larger objects remain on the surface. Try shaking a potato chip bag if you don’t believe him, the crumbs and broken crisps can be found at the bottom of the bag. It is the same theory behind the successful ABS Avalanche Airbag. Technically it is called inverse segregation but Dale prefers the “Brazil nut effect” because smaller nuts sink to the bottom of the cereal bowl.
Over the last 30 years 1748 people were caught in avalanches in the United States but only 18% (309) were buried. Those figures exclude less serious incidents that go unreported. Dale estimates the real burial figure to be closer to 10%. Atkins says that the most important thing to do if buried is to maintain a breathing space around your mouth. In twenty years of investigating incidents and nearly three decades of pulling bodies out of the snow Dale says the most striking factor was no breathing space and hands a long way from the face. If victims are frantically flailing with their arms it is hard to make a space in the second when the slide comes to a rapid halt and solidifies. Victims have described how they could not even open their eyelids due to the pressure of the snow, it was as if entombed in concrete.
The most important thing is to get rid of anchors such as ski poles (you shouldn’t have pole loops anyway) and skis but to keep your rucksack - it adds volume and helps protects your back if carried over rocks or cliffs. Although many survivors describe how they swam to stay on the surface Atkins says it was their volume, not swimming, that really kept them afloat and compares the advice to a course of leeches, if people survive the doctors claim that the leeches did the trick.
At PisteHors we’ve long been dubious about the swimming theory. If you are caught in a hard slab avalanche you have little control over events but in a softer slab getting rid of anchors seems to be the most important factor followed by trying to make an airspace or get an arm above the slide as it comes to a stop. Survivors have told us that “the swimming advice obviously comes from people who have never been caught in an avalanche”, that they felt like a “rag doll in a washing machine”.
Posted by davidof
on Monday, 22 January, 2007 at 04:14 PM
Swimming, flailing, waving; does any of that matter if your strapped to a snowboard? I have this belief that snowboarders have a greater chance of remaining on their feet but once that position is lost there is a greater chance of physical damage if swept away. It would seem clear that once dismounted those of us bolted to a single piece of wood have even less room for manoeuvre. Is there data to suggest that this supposition is correct? Is there a market for a quick release system?
Posted by on Monday, 22 January, 2007 at 08:21 PM
I have been caught in a soft slab avalanche. While my skis were trying to drag me under, my arms spread out on the surface kept me there, skis poppoing off eventually
Posted by Paddy Doogan on Monday, 22 January, 2007 at 09:58 PM
The snow board comment is interesting as I recall having to dig a guy out in Serre Che who had been caught by a very minor slide in a narrow gully. He was literally buried only to his knees but utterly stuck by the weight of snow and the ‘consolidating effect’ of the harder he struggled the more he set in the snow.
We had to use a ski tail to dig him out, I am ashamed to say we did not have any shovels to hand.
I believe though that above a certain size of avalanche it would appear to be irrelevant what you have on your feet as apparently your limbs take on a life of their own, I remember a very graphic description at a Glenmore Lodge avalanche course many years ago very much on the lines of the rag doll in a washing machine analogy.... coupled with a slide show. Amazing what sticks in your mind!
Posted by on Tuesday, 23 January, 2007 at 12:53 AM
Dale’s comments are not accepted by everyone. Bruce Tremper made a good observation “choice is the one thing you have before you are caught in avalanche but never afterwards”. In other words once you are in a slide things can be pretty random so the key should be avalanche avoidance.
I spoke to a friend who was caught in a slide a few years back. He had his pole loops on his wrists and said that the forces on his bones were fearsome.
I’ve only been caught in a small hard slab slide, the slabs shatter like a pane of glass and start hitting you like a boxer, it is not really possible to swim in the debris. This accident was in the Jura.
I’m not sure what the solution is for snowboarders and of course ski tourers using leashes have a similar problem. Someone I know who was caught in a slide in Corsica last winter actually had enough time to release his skis before the avalanche came to a halt. He’s still not skiing again due to the injuries sustained.
Posted by davidof
on Tuesday, 23 January, 2007 at 04:29 PM
I have seen pictures of quick release mechanisms set up by boarders for if they are caught in an avalanche. Not enough of an expert on snowboard bindings to say more than that, nor do I know whether they have ever been used in a real situation.
Posted by on Tuesday, 23 January, 2007 at 08:38 PM