Comments on: Avalung As Celebrity — Danger of Over Exposure? http://www.wildsnow.com/1681/avalanche-avalung-2/ Backcountry Skiing Weblog Blog, FAQs, more, links and info about randonnee, telemark and backcountry ski mountaineering. Thu, 09 Feb 2012 05:43:15 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Fernando Pereira http://www.wildsnow.com/1681/avalanche-avalung-2/comment-page-1/#comment-13867 Fernando Pereira Tue, 10 Feb 2009 03:46:17 +0000 http://www.wildsnow.com/?p=1681#comment-13867 @Jason: The risk homeostasis hypothesis is not math. Math is true by construction. When I did a pretty extensive literature search a couple of years ago, I found more experimental evidence against risk homeostasis than for it. If you do want to think about the math: a working homeostatic system (like a thermostat) requires a way of sensing the effect its actions on the environment. Some safety devices, like antilock brakes, do provide feedback in the sense that their use leads to a visible reduction of a risk-related variable (stopping distance for antilock breaks). For those safety devices, risk homeostasis may well happen. But for devices with no visible effect except in catastrophic failure (like avalungs, abs packs, transceivers), no mechanism has been postulated that could support the maintenance of some level of acceptable risk, since use of the device does not change some preceivable risk-related variable. @Jason: The risk homeostasis hypothesis is not math. Math is true by construction. When I did a pretty extensive literature search a couple of years ago, I found more experimental evidence against risk homeostasis than for it. If you do want to think about the math: a working homeostatic system (like a thermostat) requires a way of sensing the effect its actions on the environment. Some safety devices, like antilock brakes, do provide feedback in the sense that their use leads to a visible reduction of a risk-related variable (stopping distance for antilock breaks). For those safety devices, risk homeostasis may well happen. But for devices with no visible effect except in catastrophic failure (like avalungs, abs packs, transceivers), no mechanism has been postulated that could support the maintenance of some level of acceptable risk, since use of the device does not change some preceivable risk-related variable.

]]> By: Jon http://www.wildsnow.com/1681/avalanche-avalung-2/comment-page-1/#comment-13791 Jon Fri, 06 Feb 2009 16:24:39 +0000 http://www.wildsnow.com/?p=1681#comment-13791 Great points. To me, the air bags offer such proven protection, that's got to be the first choice (I'm personally waiting for the BCA system next year). So, then the question is whether the avalung adds anything significant. Seems like pulling the trigger on the air big is enough to worry about, IHMO. Great points.

To me, the air bags offer such proven protection, that’s got to be the first choice (I’m personally waiting for the BCA system next year). So, then the question is whether the avalung adds anything significant. Seems like pulling the trigger on the air big is enough to worry about, IHMO.

]]> By: Lou http://www.wildsnow.com/1681/avalanche-avalung-2/comment-page-1/#comment-13789 Lou Fri, 06 Feb 2009 16:00:06 +0000 http://www.wildsnow.com/?p=1681#comment-13789 Jon, what I'm saying is that's a decision I don't want to make but the Snow Pulse requires me to make. It seems to me that the only way an airbag will work reliably is if you trigger it at the first instant you think you're in a slide, otherwise you might not get a chance. If you trigger the Snow Pulse, you are essentially giving up control at that moment, in my opinion. I think the Snow Pulse would be much better if it just had a cervical collar that inflated for protection, rather than that big huge thing around your head. But hey, I could be wrong, someday real world use of this stuff will develop enough data to give us the true story. Jon, what I’m saying is that’s a decision I don’t want to make but the Snow Pulse requires me to make. It seems to me that the only way an airbag will work reliably is if you trigger it at the first instant you think you’re in a slide, otherwise you might not get a chance. If you trigger the Snow Pulse, you are essentially giving up control at that moment, in my opinion. I think the Snow Pulse would be much better if it just had a cervical collar that inflated for protection, rather than that big huge thing around your head. But hey, I could be wrong, someday real world use of this stuff will develop enough data to give us the true story.

]]> By: Jon http://www.wildsnow.com/1681/avalanche-avalung-2/comment-page-1/#comment-13787 Jon Fri, 06 Feb 2009 15:37:55 +0000 http://www.wildsnow.com/?p=1681#comment-13787 Lou: Can you clarify---is that to say that in order not to compromise your vision and head movement you wouldn't deploy the bag until you sensed the slide was propogating (and no chance of getting out of it)? Lou: Can you clarify—is that to say that in order not to compromise your vision and head movement you wouldn’t deploy the bag until you sensed the slide was propogating (and no chance of getting out of it)?

]]> By: Lou http://www.wildsnow.com/1681/avalanche-avalung-2/comment-page-1/#comment-13786 Lou Fri, 06 Feb 2009 14:09:57 +0000 http://www.wildsnow.com/?p=1681#comment-13786 Miller, in my opinion I'd rather my vision and head movement not be compromised. Once a slide seems to be triggered it can be very small at first then propogate to something huge that's certain death even with an air bag. At the first stage, you still want to trigger the air bag but also should be trying to ski, roll, or swim out of it, you'd never want to give up immediately and just ride it, which is what the Snowpulse design seems to assume. Miller, in my opinion I’d rather my vision and head movement not be compromised. Once a slide seems to be triggered it can be very small at first then propogate to something huge that’s certain death even with an air bag. At the first stage, you still want to trigger the air bag but also should be trying to ski, roll, or swim out of it, you’d never want to give up immediately and just ride it, which is what the Snowpulse design seems to assume.

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