Avalanche Airbag Backpack – Use One or Not?

So, you’re thinking about an avalanche airbag backpack for ski touring or other backcountry snowsports?

Avalanche airbag statistics have been available for years now. The numbers demonstrate impressive effectiveness at keeping an avalanche victim from being buried, which depending on factors such as terrain (cliffs?) and the size of the avalanche (trauma?) may result in a significantly greater chance of surviving being caught in a slide.

Nonetheless, the effectiveness of avalanche airbags is frequently overstated by media and subject to overconfidence by the public. We consumers appear to be making assumptions about increases in safety that are over optimistic. See an explanation here.) In this linked article, author Bruce Tremper makes a math supported statistical argument to the following effect:

Tremper: “…avalanche airbag packs will probably save a little more than half of those who would have otherwise have died in an avalanche. They will never save all of them because 1 out of 4 will likely die from trauma of hitting trees and rocks on the way down and an additional 1 out of 4 will probably end up in a terrain trap (deep burial), buried by a secondary avalanche or caught in an avalanche that does not travel far enough for the inverse segregation process to work (larger objects rise to the surface)…In terrain with few obstacles, terrain traps, sharp transitions and [in] smaller paths, avalanche airbags have the potential to save significantly more than half of those who would have otherwise died.

We would add that in smaller avalanches, you many not be entrained in a lengthy or large enough flow to instigate the “inverse density” effect that allows the airbag to keep you on the avalanche surface. Compounding that, in a smaller slide a delay in when you activate the airbag can result in very little time until the slide comes to a stop — possibly not enough time for the “flotation” effect to occur.

Conclusion: If you backcountry ski you probably will want to rock an airbag backpack, but at the same time you’ll need to continue to refine your assessment and judgment skills. If you expect the airbag to make up for clueless blundering, think again.

We won’t go too into the science of how avalanche airbags work but basically they rely on the principle of inverse segregation. If you shake a bag full of sand and pebbles, the pebbles will rise to the surface as they have more volume than the sand grains (this also works with a bag of popcorn or or tortilla chips; the big particles work their way to the top). Thus, in avalanches, making yourself bigger can help keep you on the surface, air bags do that by inflating a bag-balloon which increases your size. Technically speaking, you’re not really “floated” to the surface of the avalanche, but the effect is similar.

As opposed to an avalanche beacon which relies on disciplined friends to find you and is therefore a passive safety system, airbags are an active system that you can purchase and use to increase your personal odds of survival.

To drive the point home, know that the chances of being dug up alive by your friends are actually not all that good. In a study by the Swiss Federal Institute for Snow and Avalanche Research, 53% of people completely buried by avalanches did not survive, while only 4% of those who weren’t buried died. Your best bet is to stay on the surface, and an air bag provides a significantly better chance of that happening.

Perhaps the biggest deal with avalanche airbag backpacks is they have a cost. They cost you comfort and calories as they weigh significantly more than a normal rucksack, they cost time as they need to be practiced with, repacked and refilled — and they cost way more coin. Thus, you’ve got a cost/benefit ratio you may want to consider for your own situation.

For example, say you’re an extreme alpinist who usually uses skis simply as an approach and egress tool, will you carry an extra kilo of more of weight just to have an airbag for a bit of skiing after your climb? Or, are you truly so strapped financially you’re wondering how to buy your next meal? Good judgment and technique trumps all safety gear, so the big spend on an airbag is not mandatory.

Likewise, the weight and hassle of airbag packs may be too high a cost if you do much air traveling. Perhaps you’re better off renting at your destination, or just not using one and instead allocating your energy and finances to good decision making and guide fees.

Also consider the type of terrain you ski (see Tremper quote above). Airbags are most effective in moderately sized avalanche in open terrain without trauma inducing features such as trees and cliffs. An airbag won’t help you in a huge avalanche that damages you from trauma, and it won’t help you in a tiny slide that could bury you in a terrain trap before there’s time or opportunity for the “separation effect” to keep you on the surface.

If cost is an issue but you do ski the type of terrain where an airbag could be effective, think it through. Many skiers don’t flinch at dropping more than $1000 on new skis, boots, and bindings each season, so is spending that much (or less) on a safety device really that big a deal? Or consider snow tires? You might flinch at the tire store, but you still get the new meats and enjoy the feeling of being able to stop at an iced intersection without gliding effortlessly to the bumper of the garbage truck coming in from your right. In our opinion here at Wildsnow.com (with caveats, see below) it is time to set priorities and make air bag packs just as important as your beacon/shovel/probe combo (indeed, if forced to choose, in many situations you’d actually be better off with just the airbag).

What we’re writing about here is in the NOW, when airbags are expensive and complicated. In terms of the future, know we do feel avalanche airbag backpacks will eventually achieve a level of standardization and efficiency, and lower price, that makes them similar to the now ubiquitous and socially mandatory beacon — in other words, sporting an avalanche airbag ruck will pretty much be status quo.

Use- All airbag packs have a handle (“trigger”) located on one of the shoulder straps for activating the airbag. When in safe terrain or in situations such as riding a helicopter, the handle can be stowed out of reach to avoid an accidental activation (something to be wary of while bushwacking, or even getting gear in our out of an automobile). When ready to ski, put the handle in the ready position, and if (God forbid) you need to use it, pull on the handle which causes a container full of compressed gas to inflate the airbag (or a powerful fan in the case of Black Diamond Jetforce).

In an avalanche, your body and air bag are subjected to tremendous forces. In order for the rucksack to not come off you in an avalanche, the hip belts use specially “safety” shaped metal buckles, which are much more cumbersome than standard plastic buckles but are needed for strength. In addition, a leg or crotch loop is supplied to prevent the pack from being pulled up over your head. These are a pain to use but absolutely necessary. After use, the fabric balloon needs to be deflated and repacked, and in the case of gas powered packs you’ll need to replace or refill your “tank.”

Testing and Refilling- When you first get your airbag pack, you should perform a test release to familiarize yourself with the process and to make sure it works. Ideally, you should do this while wearing everything you would wear while skiing (or at least goggles, jacket, and your least dexterous pair of gloves or mitts). For extra points do your test while skiing on a safe slope. Then, depending on the system you have, you will either have to refill or replace the gas cylinder (or recharge your battery if you’re using a fan type of system). You should test your bag at least once a season to re-familiarize yourself with the deployment and to make sure it works — along with checking that your bag stowage is being done correctly. We recommend several tests a season, good reason for an easily refillable or rechargeable system.

BCA, Mammut and Snowpulse use a cylinder system with a gauge (not a “cartridge,” which is a factory sealed tank) that the user can refill with compressed air at certain locations. They recommend using licensed retailers, but any paintball shop can do it or any dive shop or fire station if you have the correct adaptor. Dive shops require a paintball to SCUBA adaptor, while fire stations require a paintball to SCBA adaptor. Your home compressor or gas station won’t cut it, you need 2700-3000psi (varies by manufacturer). We have found some fire stations to be very helpful and accommodating, they probably won’t charge you anything so be sure to make a donation to keep them happy and always call in advance.

Also, when the cylinder is filled from a compressed gas pump, it will get very hot; you must let it cool down and then top off again (gas expands when it is hot), a water bath will work for this. After refill, the O-ring must be replaced and silicone grease reapplied, then everything sealed up again to keep water out. It’s a bit of a ‘DIY’ project, but very doable if you follow the instructions. We love having the freedom to refill when I need and not having to deal with any shipping (or the cost of buying cylinders such as Alpride). One other thing, regardless of how you get the cylinder filled, there is a two step process to attaching it to the pack. The cable that goes to the activation handle must be attached to the release pin (don’t accidentally pull it out!), and the valve must be attached to the plumbing that goes to the air bags. Not difficult, but not as idiot proof as ABS.

Air Travel- Flying with your air bag backpack is not a terribly difficult thing in most of the world, provided you notify the airline in advance, follow the instructions provided by the manufacturer, carry the material safety data sheet and perhaps the relevant airline regulations (download off your manufacturer’s website).

If you’re traveling to/from/within North America, for the most reliable results when using a refillable system, bring an empty cylinder with the cap removed for inspection, and get a fill at your destination. In the case of non-refillable cartridges your best bet is to leave the filled bottle at home and acquire another at your destination. Nonetheless, stories abound of placing a non-refillable pressurized cartridge in your checked bags and it being there when you arrive — but not always.

As of 2014 Europe has specific rules regarding avalanche airbags and you can fly European with filled cylinders, though we’re still confused as to whether we’re supposed to carry our full cylinders/cartridges in checked baggage or in carry-on.

Fan systems such as Black Diamond Jetforce are no different than carrying a laptop computer with a battery, and are said to be allowed either as carry-on or checked baggage, though you should make sure everything is stowed neatly and safely as any battery does have an innate fire hazard.

Alpride is said to be the most airflight compatible of the compressed gas packs because it uses the same type of cylinders as the life jacket under your airline seat (need a replacement, just wait till the flight attendant isn’t looking!). Still, we’ve been confused as to whether we’re supposed to carry the Alpride cylinders attached to the rucksack plumbing or as originally blister packs, and whether they should be in checked baggage or carry-on.

In all, it’s tragic the airbag industry as a whole has not done a better job of clarifying and simplifying the air travel issue, but we’ve seen much improvement so we’re optimistic.

Studies and Data-There have been several tests of the effectiveness of air bag packs, and they are further validated by the substantial records of real world accidents. Please take the time to google and browse the data for yourself.

Commenters, suggestions welcome for studies we can link to. Unfortunately many of the poorly managed airbag websites remove content with no effort to provide redirects, so we end up with broken external links. More, we caution against placing too much stock in personal accounts that that claim “my airbag saved my life!” Even without an airbag, many avalanche victims end up on the snow surface. It’s usually (if not always) impossible to determine in individual cases whether a person would have been otherwise buried if they’d not been using an airbag. News media and marketing people tend to confuse cause with results in this case, e.g., “I was wearing SuperSkier brand goggles, survived the avalanche, and thus my SuperSkier goggles saved my life!” Studies that do rigorous statistical analysis are much more valuable than “SuperSkier” types of stories.

Backcountry Access does a terrific job of keeping their research content available. Check it out here.

Important: Please see our Avalanche Airbag Backpack Overview for our specific up-to-date report on what’s available in this category of backcountry skiing gear.

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