Avalanche airbags, how effective are they really?

[neck beard]

That is because, in the first case, both you guys probably think like backcountry skiers with a defined personal appetite for risk based on a certain understanding of what is going on around you, and a respect for how little you know at any point in time.

A significant percentage of people who find themselves in avalanche terrain do not think like backcountry skiers - because they aren't. They have no awareness at all of the risks they are surrounded by other than the fact that "it might slide", they over estimate their abilities and confuse luck for good judgment. Those people should probably back away from the terrain that appeals to them, but they won't, the'll buy an airbag... just in case.

This may end up helping them, but without the airbag, perhaps they may have helped themselves with a little humility, respect, education, and experience in simple terrain.

On the flip-side, with good technology, the need for humility, respect, education, and experience in simple terrain doesn't mater nearly as much. So who cares if people don't have it? Let them do what they damned well want.

[Lizhnik]

I would also like to hear about the cases when it didn't work perfectly.

The high forces let often to an upshift of the backback on the dummy bodies resulting in the hip belt being directly below the chin. Although the leg loops are practically never used by skiers, their usage seems advisable

I posted about this in the Slide Zone several years ago when it happened, but I witnessed an avalanche where a skier was caught and managed to deploy his ABS. However, he was not wearing the leg straps and the force of the avalanche tore the hip belt at the seam and ripped the entire backpack off of him. The pack and balloon were lying on the surface while the skier was completely buried several meters away from the pack, though not very deeply (under .5 meter). He was recovered and survived with minor trauma. A second skier was also buried by the slide. She did not have an ABS, was buried much more deeply (1.5-2 meters) and did not survive.

[skimaxpower]

^^ Wow. Telling story.

[Scottish_Skier]

I think there is enough evidence to suggest that airbags work well.
However...

ABS has statistics which state that 97% survive

This 97% is fundamentally flawed maths IMHO.

According to the SLF (swiss avalanche bureau) less than 30% of people involved in large avalanche incidents are actually buried. These figures are based on reported avalanches (often avalanches will go totally unrecorded unless someone is hurt).

Clearly this means that not everyone who pulls the trigger on an ABS pack would have been otherwise buried with out it . However ABS take no account of this when compiling the final 97% survival figure. Dont know how you could mathmatically come up with a more accurate %? However I think its wrong to advertise figures that suggest ABS makes you 97% immune from avalanche danger ?

Several recent cases in Europe & USA recently where victims with deployed airbags have died of serious trauma.

[marshalolson]

you can play with %'s about seatbelts/airbags in cars or whatever too.

the actual % is irrelevant. why are people so hung up on them?

its safety gear. its safer with it than without. if you sustain an injury it will likely be less severe than if you didn't have it, but it could still be very severe or deadly. safety gear is about minimizing the damage, not totally eradicating any danger. skiing avalanche terrain is dangerous. having an airbag does not remove or trivialize that danger. thinking that it will shield you from death/injury is totally naive. letting it effect a go/no go choice is ridiculous. if you think something can/will slide, don't ski it. nobody WANTS to be in a slide, and thinks they are invincible with an airbag.

is there an argument that airbags are somehow less safe (i.e. they will cause more harm to someone) than no bag? no? then what the hell!

i mean do people with helmets intentionally ski straight into rock walls? the chance of a concussion is smaller.... right?

who cares if its 97 or 95 or 90 or 50 or whatever. that number is meaningless. either you get buried, racked hard over rocks or you stay up higher and avoid alot of that. its not like if you don't get hurt, avalanches are fun. nobody thinks they are fun. they are scary as shit, and something everyone would prefer to never experience, and those that DO experience it, even WITH an airbag would very much prefer to stay far away from another one.

[srsosbso]

Good article, with good data analysis and interesting text.
http://beaconreviews.com/transceiver...tz.TAR30.4.pdf
To me, the most interesting stat is the fatality rate of non-ABS wearing partners of ABS wearers, ie. 25% dead vs. 3%. Pretty compelling data.

[Driver]

Great article by Jonathan with the real hard Data. I particularly like the approach of thinking about it in terms of how many who died would have survived, as opposed to how many survived who were caught. Data in the 35-81% range is a pretty compelling point in favor of the airbag. Obviously the stat has to be qualified given it is a counter factual, but still interesting.

[davidof]

This is an article I wrote about airbags a couple of years ago following some French fatalies

http://pistehors.com/news/ski/commen...k-homeostatis/

[Beyond]

Good article, with good data analysis and interesting text.
http://beaconreviews.com/transceiver...tz.TAR30.4.pdf
To me, the most interesting stat is the fatality rate of non-ABS wearing partners of ABS wearers, ie. 25% dead vs. 3%. Pretty compelling data.

Am I misreading the data chart - and text - or did the Colorado analysis come out with 91% survival without airbags? If that's what the findings were, would look forward to someone unwrapping that. Suspect it may reflect a much broader definition of what constitutes an avalanche, and obviously a different design than a matched comparison for each lethal slide, but still....

Also, totally agree with Marshal that culling over specific numbers and honing confidence intervals is entertaining, but even if bags only boosted survival by a few % (and it looks a lot stronger effect that that), we routinely embrace technology that gives us a very non-dramatic edge in an adverse event. Cars come to mind, but so do helmets, or most of all CPR, which saves well under 10% of victims it's used on. Even a few % better outcome makes a difference if you're the one saved by that rock not quite penetrating your helmet this time, or being buried high enough in the snow that your friends can dig you out a couple of minutes faster.

[srsosbso]

91 percent indeed. Probably a difference based on reporting one might guess.
I think the reason people are looking at the degree of improved survival is based on cost, both monetary and weight of gear.

[Beyond]

^^^^ Agree. Cost/benefit. And packs are a PITA, even if fact of life for many. But also think risk denial figures in - just the way our brains work. Probably won't happen to me, so...

[srsosbso]

Been in one, so no longer in that category, unfortunately. Very interested in these.

[Jethro]

How can it be page 3 and I have not read Rog's opinion yet?

[neck beard]

TGR = Teton Gravity Rog

[davidof]

But also think risk denial figures in - just the way our brains work. Probably won't happen to me, so...

it probably wont.

The 91% figure is taking all reported avalanches over the period I believe. It was in the TAR a while back. It is probably as reasonable as the ABS 97% figure but the 6% increase in survivability is as unfair as ABS's 97% figure. One makes the ABS look like the miracle solution to avalanche survivability and the other like a dubious piece of extra baggage.

I know guys who have pulled their ABS in obviously minor slides and are then telling the story back at base "dudes, that airbag saved my life today" when they were obviously just going a few feet on a surface slide. Still that surface slide could have taken another lower slab so they made the right choice.

[srsosbso]

This conversation inspired me to post my own experience from a year and a half ago, here...
http://www.tetongravity.com/forums/s...essons-learned

[EEC]

They've done studies you know. 60% of the time it works every time.

[NickAdams]

Anyone recommend an airbag option with a pack bag that is big enough for multi-day tours?

[justr]

In thinking about improved survival stats and cost/benefit of airbags in perspective... what are the survival stats w and w/o beacons shovels and probes (and partners that know how to use them)?

What if the bags offer a better survival improvement than traditional avy gear? Would they still seem I) overpriced for the benefit by some or II) a second purchase after the traditional gear (assuming your whole crew acts as one on this)?

[icelanticskier]

How can it be page 3 and I have not read Rog's opinion yet?

haha!

late to the party

i've been in an avy but have no interest in the bag. gonna go about bidness per usual with an ever increasing understanding of where i've gone wrong in the past and trying not to make the same mistakes in the future.

steep nuff slope angle, new snow/slab, sliding surface, and trigger. take any one away and it's all good. simple. now if only can keep reminding myself...........

edit to add: helmets. after skiing yesterday and being one of a few that does not wear a helmet, i can see why so many do. almost everyone i saw wearing one was skiing way too fast for their own good and a lot of them were barely in control. those people should wear them, i agree.

rog

[TheDon]

edit to add: helmets. after skiing yesterday and being one of a few that does not wear a helmet, i can see why so many do. almost everyone i saw wearing one was skiing way too fast for their own good and a lot of them were barely in control. those people should wear them, i agree.

rog

We are slowly breaking you... little by little, soon you will be in a dome with an orange balloon on your back.

[Jonathan S.]

who cares if its 97 or 95 or 90 or 50 or whatever. that number is meaningless.

Because if it was only, say, a 1% reduction in fatalities, then we’d be better off devoting that extra weight to an AED, or all sorts of other emergency supplies.
(But as my analyses of the various data sets show, it’s a far far far higher % reduction in fatalities.)

Am I misreading the data chart - and text - or did the Colorado analysis come out with 91% survival without airbags? If that's what the findings were, would look forward to someone unwrapping that. Suspect it may reflect a much broader definition of what constitutes an avalanche, and obviously a different design than a matched comparison for each lethal slide, but still....

The definition of an avalanche is the same, but it’s the “in” an avalanche part that is hard to define.

The 91% figure is taking all reported avalanches over the period I believe. It was in the TAR a while back. It is probably as reasonable as the ABS 97% figure but the 6% increase in survivability is as unfair as ABS's 97% figure. One makes the ABS look like the miracle solution to avalanche survivability and the other like a dubious piece of extra baggage.

Even if both the 91% and 97% are addressing comparable definitions of being “in” an avalanche, that 6% differential actually equates to a 35% reduction in fatalities.

BTW, more detailed and updated analysis here (although specific to Canada):
http://www.avalancheresearch.ca/

In thinking about improved survival stats and cost/benefit of airbags in perspective... what are the survival stats w and w/o beacons shovels and probes (and partners that know how to use them)?

What if the bags offer a better survival improvement than traditional avy gear? Would they still seem I) overpriced for the benefit by some or II) a second purchase after the traditional gear (assuming your whole crew acts as one on this)?

http://www.liebertonline.com/doi/abs.../ham.2005.6.72
"The Impact of Avalanche Transceivers on Mortality from Avalanche Accidents"
Matthias Hohlrieder, Peter Mair, Walter Wuertl, Hermann Brugger
High Altitude Medicine & Biology. Spring 2005, 6(1): 72-77

"Avalanche transceivers were used by 156 (56%) victims and were associated with a significant reduction in median burial time from 102 to 20 min (p < 0.001), as well as a significant reduction in mortality from 68.0% to 53.8% (p = 0.011). This reduction was due to a decrease in mortality during backcountry activities involving ski tourers in free alpine areas (from 78.9% to 50.4%, p < 0.001). Transceivers did not reduce mortality during off-piste activities beside or near organized ski slopes (67.7% with versus 58.5% without transceiver, not significant)."

Here is how I explain that to my avy students:

Full Burial Calculations for Backcountry Activities in "Free Alpine Areas":
78.9% mortality rate, no avalanche beacons
50.4% mortality rate, with avalanche beacons
21.1% chance of survival, no avalanche beacons
49.6% chance of survival, with avalanche beacons
135% percentage increase in survival chance from beacon use
In other words, out of 100 fully buried victims engaged in backcountry activities:
21 survivors out of 100 victims, no avalanche beacons
50 survivors out of 100 victims, with avalanche beacons
2.4 ratio of with-beacon survivors to no-beacon survivors

To illustrate this, have 10 people come to the front of the room.
Everybody down on the floor -- you're fully buried.
And none of you have beacons.
I tap two people -- you can get up, you live.
Now let's pretend instead that all of you have beacons.
I tap three more people -- you too get to live.
Still, 5 out of 10 buried people are still lying there dead, so not all that great a result, but far better than without beacons.
(Note that the beacon searches in the study by necessity include a wide range of search skills -- improved searching skills would increase the survival probability even more.)


Also, two quick plugs – since my article was referenced from BeaconReviews.com, here’s the page we recently updated to include some really basic criteria when choosing an airbag pack:
http://beaconreviews.com/transceivers/Airbags.asp

And for additional continuing education on all things avalanche, I highly recommend subscribing to The Avalanche Review (where my article was published):
http://www.americanavalancheassociat...blications.php

[icelanticskier]

We are slowly breaking you... little by little, soon you will be in a dome with an orange balloon on your back.

never gonna happen. that i assure you

rog