Just a few years ago, avalanche airbag use was very rare, especially in the US. But now, we can chose from multiple options such as ABS, Snowpulse/Mammut, Backcountry Access, and WARY/Mystery Ranch, with a multitude more to come in the 2013/2014 winter season. Although the evidence is overwhelmingly compelling that airbag packs work (we have all seen the statistic that 97% of people survive an avalanche when wearing an avalanche airbag pack), but exactly what these statistics mean can be open to interpretation.
Bruce Temper over at the Utah Avalanche Center recently wrote a thought provoking post highlighting how that 97% survival statistic can be misleading. As is with all numbers, they can be manipulated to to suit almost any purpose or point of view. Bruce points out that nobody talks about that number in comparison to your chance of survival without an avalanche airbag.
According to the data from the Swiss Federal Institute of Snow and Avalanche Research (SLF), you have around an 81% chance of surviving an avalanche if you are caught up in one, meaning you will either escape off the slab, grab a tree, dig into the bed surface, ride on top of the debris, it will be a small avalanche that wouldn’t bury you anyway, you could be saved by a beacon recovery, or you could simply just get lucky.
That extra 16% chance looks pretty small when compared to the cost (price and weight), but what if you look at the numbers only involving avalanches where the avalanche airbag could have actually been effective, i.e., where you couldn't have survived it by skiing out or by some other means.
In the April 2012 issue of the Avalanche Review, Jonathan Shefftz trolled through five different published data sets and found that wearing an avalanche airbag would have saved from 35 to 81 people out of 100 who would have otherwise died, with the average of all the data sitting at 64. So, it seems that in real-world experience, wearing an avalanche airbag will possibly save a little more than half of those who would have otherwise died, not quite the 97% commonly advertised.
Your choice of terrain is also extremely important. Un-survivable terrain will always be un-survivable. In terrain with few obstacles, terrain traps, sharp transitions and smaller paths, avalanche airbags have the potential to save significantly more than half of those who would have otherwise died. Those numbers still sound pretty good as most of us probably ski this less severe terrain.
Looking at the real avalanche airbag effectiveness statistics brings up a few questions. Is telling people that they have a 97% survival rate when wearing an avalanche airbag misleading and causing people to take more risk in the backcountry? As with avalanche beacons, does the industry have the obligation to help make airbags more prevalent (i.e., more affordable) and easy to use if they really are going to save over half of the skiers or snowboarders who might otherwise had died?
I would love to hear your thoughts.