Avalanche airbags, how effective are they really?

[Gurterno]

Last week we tragically had an avalanche which killed two men (leaving behind a total of 7 children) who were touring in Northern Norway. It was a large avalanche, 2-300m wide, 0.3-1.5m thick at the top and it travelled 650m. One of the deceased had an airbag which was deployed but he was buried at 1-1.5m depth. There will be a full report on this by the authorities when they have all the facts. In Norwegian:

http://translate.google.com/translat...2FEnormt-skred

I understand airbags isn’t a guarantee against beeing buried but it got me thinking. I am, like most people, considering buying one of these packs and I’m wondering which one and should I get one at all? ABS has statistics which state that 97% survive. When I see the number 97% I almost automaticly think ”everyone”. It chocked me a bit when I heard he had a deployed airbag.

http://www.abs-airbag.com/

http://www.slf.ch/

I don’t understand german but here’s a guy who obviously doesn’t fully trust all the facts stated by ABS-airbags:

Do you know of other accidents where the victims have deployed their airbags and still been totally buried, balloons and all?

Last year a guy in my local skiarea had one of his balloons in his ABS-pack punctured when he was caught by an avalanche. Since then I have always thought of the ABS-pack to be safer then the rest because of the redundancy of 2 balloons. But after watching the youtube video above I may be prone to thinking that the snowpulse system would be better at keeping your head above the snow. I don’t understand why they can’t divide the balloon into two so that half would stay inflated even if it’s punctured.

A lot of people are starting to wear theese bags now. I would like to hear all stories of actual avalanches with victims who had airbags. What’s your experience?

Did they stay on top and do you believe it was because of the airbag?

[Poop~Ghost]

redunancy doesn't mean much IMO w/ regards to puncturing a airbag. If one get's punctured - the remaining one will not likely be big enough to keep you afloat.

It's the brazil nut effect that is keeping you ontop - which doesn't mean that you'll necessary stay on top the whole time.

Avy-ing through trees is going to be a disaster almost any way you slice it.

[hutash]

Size matters too. That sounds like a pretty big slide, so chances of a burial are going to go up. Other then not getting caught in a slide airbags are still your best bet at surviving a slide, but there is no guarantee.

[njfreeskier]

If you look at the multiple fatality avy at steven's pass...of the 5 (i believe) people who were caught in the slide the only one that survived was Elyse Saugstad, who was the only one to have and deploy her airbag. When interviewed she gives full credit to the airbag being the reason she was only partially buried, and thus surviving the avy.

Sounds like a pretty good case of them being extremely effective.

[skimaxpower]

If you look at the multiple fatality avy at steven's pass...of the 5 (i believe) people who were caught in the slide the only one that survived was Elyse Saugstad, who was the only one to have and deploy her airbag.

For factual accuracy, I believe that this slide had:
-3 fatalities
-1 survivor who bear-hugged a tree
-1 survivor (Elyse) who wore an ABS
-8(ish?) survivors who were above the slide and participated in the rescue

[Core Shot]

there have been lots of tests with avys large and small, using mannequins with and without ABS

ABS always does better in those tests, but every now and then one gets buried.
Terrain, snow texture, size, etc. all have an effect on flotation.

Universally it is agreed they work.

What I worry about is what it does to the heuristics.

will more skiers die with ABS since they feel protected and take more risks??

It has been said that with a beacon, you should still ski as if you have none.
burial is only part of your battle. Trauma (even without trees) can do you in.

[mc_roon]

What I worry about is what it does to the heuristics.

This. If people start taking bigger risks because they have a airbag, it will negate the benefit of the bag in the first place.

Also worth noting that a lot of the tests(both company R&D and actual usage in a slide) that resulted in the statistics these companies claim were carried out in Europe and BC, where more of the terrain is above treeline. In most areas in the US we are either below the tree line or a slide could carry us into the tree line, resulting in punctured airbags and more deaths due to trauma then in other regions.

But if you can have an ABS on without letting it changing your backcountry habits, it's a great thing.

[Driver]

This. If people start taking bigger risks because they have a airbag, it will negate the benefit of the bag in the first place.

^^^ This. It should give you pause that someone was wearing an airbag and still did not make it. This comment is in NO way related to who specifically has or has not survived because those instances are specific and I know nothing about them, but I have like others been very worried that more and more people will think they need less training, knowlege, and facility with the basic tools of the avalanche trade because an airbag saves you "97% of the time".

On the statistic itself, this is likely an incredibly misleading use of numbers. If you flipped a coin 5 times, and it came up heads 4 of those 5 times, would you try to sell me a coin as one that comes up heads 80% of the time? I highly doubt the 97% number is statistically significant (in statistics parlance), meaning, the low number of observations means using a statisic like this meaningless. There are also a lot of qualitative factors affecting the statistic: was the slide someone survived with an airbag likely to bury you if you were not wearing the airbag? This is impossible to know, calling into question to legitimacy of the 97% number (or any number), no matter how many observations are obtained.

All of this is not to say this isn't a good piece of safety equipment; it has clearly helped people and I am certainly inclined to carry one. However, this is not a safety net that can replace anything else. The fake 97% number is irresponsible because people actually take it at face value.

[mc_roon]

There are also a lot of qualitative factors affecting the statistic: was the slide someone survived with an airbag likely to bury you if you were not wearing the airbag?

At least one company (ABS i think) who purposely started slides with dummies outfitted with airbags in the slidepath also had dummies without airbags getting caught as well for a control group. While the number of times they did this is probably not statistically relevant it shows they were trying to be as accurate as possible.

[Jonathan S.]

The fake 97% number is irresponsible because people actually take it at face value.

The relatively recent switch to the singular 97% figure at the ABS website is somewhat surprising (at least to me) because through at least the 2009-10 season ABS was publishing (and periodically updating) a very detailed database of every single ABS in-the-field deployment ... both actual and attempted, as well as successful (in terms of life or death) and otherwise.

I still have the file, so that and some other non-ABS databases will be the basis for a possible article in the final issue of TAR this season.

[Alkasquawlik]

But if you can have an ABS on without letting it changing your backcountry habits, it's a great thing.

I've worn an ABS bag for three years now and wondered how it might effect my habits mindset as well. Let me tell you...it doesn't. I have never taken an additional risk with because the thought of having an ABS bag on my back might be a ticket to safety. Think of it this way. If you're looking down a slope with the potential to avalanche, do you still want to drop in even though you know you have something that "might" save you?

I didn't think so. My bc habits haven't changed one bit since wearing an ABS. It's just nice to know that if the shit does hit the fan, I have one more hope to survive beyond being unburied by my friends.

[Poop~Ghost]

I've worn an ABS bag for three years now and wondered how it might effect my habits mindset as well. Let me tell you...it doesn't. I have never taken an additional risk with because the thought of having an ABS bag on my back might be a ticket to safety. Think of it this way. If you're looking down a slope with the potential to avalanche, do you still want to drop in even though you know you have something that "might" save you?

I didn't think so. My bc habits haven't changed one bit since wearing an ABS. It's just nice to know that if the shit does hit the fan, I have one more hope to survive beyond being unburied by my friends.

Does it change the order in which you ski? The reason I ask is because I've been in an ABS for 3 years as well and a few times I've found myself saying internally "If we're wrong in our assessment of this slope and it did go before I'm safe - at least I have the ABS and the other guys don't have it" so I go first.

I don't believe it's ever changed my mind on a slope I've skied on - I tend to be one of the more cautious of my groups or at least the more vocal - but I honestly wonder if I'd know if it was changing my mindset?

I've argued w/ a number of friends and partners who think it's setting you up for getting into a looser set of habits - but I'm still of the belief that having an extra few pounds on my back is worth the last thread of hope if all else fails.

[1000-oaks]

There are a lot of factors that will determine how well the bag keeps someone afloat, or doesn't. If the ride is short the bag won't have much time to pull you to the surface (gotta shake the can of nuts a lot to bring the big nuts to the top). If someone is caught under slabs and the snow really isn't churning much, the bag can't really do it's thing. Or if the chunks of slab are larger than the person w/bag, the big chunks will stay on top. If the person is low on the hillside and the avi dumps on top of them and then halts, they just get buried.

So yeah, for best airbag results the snow is probably soft and fluffy and churns a lot, and is a long ride above treeline. Unfortunately that's exactly not the norm in the lower 48 states, but every little bit helps. I've got a MR Blackjack on order.

[Snowy Spartan]

At least one company (ABS i think) who purposely started slides with dummies outfitted with airbags in the slidepath also had dummies without airbags getting caught as well for a control group. While the number of times they did this is probably not statistically relevant it shows they were trying to be as accurate as possible.

If there's one thing I learned as a stats major in college, it is that just about every "stat" created is bullshit. You could give me hard data that basically proves one thing and I could manipulate it to prove the exact opposite.

[SiSt]

If there's one thing I learned as a stats major in college, it is that just about every "stat" created is bullshit. You could give me hard data that basically proves one thing and I could manipulate it to prove the exact opposite.

In order to get to 97%, you'll need at least 29 samples as 1/29=0,03448 which is rounded to 3%. Very interested in how they've arrived at their number, and I've started saving for a pack lately.

Sent from my GT-I9100 using TGR Forums