by Rob Coppolillo
The magic bullet, we’re all looking for it. Weight loss, financial advice, and how to avoid the chop the in the backcountry; if there were a simple solution to any of them, we’d gladly pay any price for it. But wait, when it comes to surviving avalanches, aren’t those “balloon pack” (aka: Airbag packs) things “97-percent effective,” according to one brand? Sounds pretty good, right? Sign me up?!
Yes. And no.
Turns out airbag packs are both great … and hardly the magic bullet they’re often marketed as. Read on before you pull the ripcord in either direction.
WorkSafeBC is British Columbia’s version of our OSHA (Occupational Safety and Health Administration). WorkSafe BC studies workplace safety and implements policies and regulations to protect individuals in hazardous environments. In August of 2012, Pascal Haegeli lead-authored a study of airbag packs and their efficacy in the Canadian snow environment. While several similar studies had been compiled in Europe, the Haegeli report was the first comprehensive non-Euro study.
What’s the difference, you might ask? Canadians, and to a large degree Americans, operate in more forested terrain (consider that treeline in Colorado is 11,500 feet while only 7,500 in Europe) and the use of helicopters is much more widespread in Canada (and Alaska) than in Euroland.
Haegeli and his co-authors knew the European stats indicated airbag packs improved survival rates significantly, as much as 30 percent, but were they just as effective with more trees to hit during an avalanche? Were they a hazard around helicopters?
The Canadian study analyzed 34 avalanche incidents involving 71 individuals, 46 of whom were wearing airbag packs. The study also polled 150 individuals and 90 commercial operators (heli, cat, and guiding outfits) regarding their opinions of airbag packs. The take-away was pretty simple. Within the study sample, airbag packs improved survival rates by 27 percent over non-users.
The caveat, though, was that certain terrain, slope configurations, and avalanche accidents quickly negate much of that advantage. So the question becomes — when and where to wear your fancy, new pack?
By looking at each avalanche accident, researchers were able to quickly identify what they’d already suspected. That is, airbag packs are amazingly effective in the right situations – smaller avalanches on open slopes without terrain traps present. When these conditions prevailed, survival rates jumped from 56 percent for those not wearing a balloon pack to 83 percent for those wearing one — the impressive 27 percent number from above.
Initial tests in Europe, in the ‘90s, had shown this to be the case. By staging crash-test dummies, with inflated airbags, on snow slopes and then triggering avalanches, researchers knew that airbags prevented full burials most of the time. During the few incidents in which dummies were buried, they tended to be buried near or at the surface, often times with some of the inflated bladder visible. Years of accident data went on to corroborate these data, too.
Physicists explain the phenomenon as “inverse segregation;” that is, when particles are flowing together, smaller stuff settles and larger stuff ends up on top. Shake a bowl of nuts and the brazil nuts (that’s you and your balloon pack in an avalanche) come to the surface while the sesame seeds (snow particles) settle to the bottom. Simple.
The problem was, every so often there was a fatality with an airbag pack – somebody couldn’t or didn’t deploy it, a victim was fully buried, or a person was killed by trauma despite having deployed their airbag. What gives?
The Canadian researchers knew that some of the situations in which airbags don’t necessarily improve survival are more common in Canada – forested terrain, in particular. They got down to studying their own accidents to generate their own numbers.
Authors were quick to point out their dataset was relatively small, but preliminary analysis yielded some insight. They identified a few main situations in which an airbag’s advantage is quickly negated. First, larger avalanches (D 3.5) tended to end in fatalities whether the user was wearing an airbag or not. Secondly, position within a slide was critical: those triggering a slide from lower in the track or runout zone were far more likely to be killed, regardless of whether they were wearing an airbag. Finally, if there were terrain traps present in the runout, victims were more likely to be buried and killed, with or without an airbag.
The study also raised some areas for future research. Do airbag wearers consciously or unconsciously take more risks when wearing one? Does attempting to deploy, or having an airbag pack deploy while involved in a slide, reduce the chances a skier might be able to escape?
As more recreationalists adopt airbags, time and accident data will tell.
One area of concern that’s worth highlighting is trauma. We know that worldwide 25 percent of all avalanche deaths are from trauma. Those numbers are probably higher in places like Colorado with a relatively shallow snowpack and plenty of trees. There’s been speculation both ways, that balloon packs could protect from trauma, but they might also increase it because a wearer is atop a slide where it’s moving faster.
The Canadian study declared no significant difference in trauma rates between those with and those without an airbag. One manufacturer claims the configuration of its airbag (once inflated) offers some protection, but a subjective look at the trauma fatalities in the study suggested these victims would’ve died no matter the bag they were wearing.
So, are you ready to make the big purchase, or what? Airbag packs certainly work … but only in certain terrain.
As Bruce Tremper, Director of the Forest Service Utah Avalanche Center, writes, “My pet peeve with this issue is that people who argue about the numbers often leave the most important part out of the discussion — terrain. If you get caught in un-survivable terrain then, guess what, you won’t survive no matter what kind of rescue gear you use.”
Recall that un-survivable terrain, whether we’re talking airbags or not, is any slope with trees or rocks to hit, with cliffs to get washed over, crevasses or a gully into which you can get buried — any feature that will make the consequences of an avalanche worse. Remember that bigger avalanche paths (ones capable of producing D3 avalanches or greater) negated the advantages of an airbag, too.
And don’t forget that discussion of risk. Are you willing to ski a bigger line, simply because you’re wearing an airbag pack? If the answer is “yes,” you’ve probably just negated any advantage the pack conferred upon you. Heads up.
Airbag packs work. They’re probably worth the investment. They’re no magic bullet, though. What is? Education, sound decision-making, and ultimately, choosing the right terrain for the day you’re out there getting it done. Play smart!