 Poster: A snowHead
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Hopefully this hasn’t been posted before, I didn’t find anything using the search function.
The Safeback is in effect an active version of the old Black Diamond Avalung, but you don’t need to get a mouth piece in place, as the air is pumped into the snow around your chest. If it works as designed it should extend burial survival from 20-30mins to up to 90mins, but that depends the snow type.
I can think of a few potential issues, such as face icing, but is appears to be being taken up by a number of major back pack manufacturers, so there must be something in it.
https://gearjunkie.com/winter/safeback-sbx-avalanche-safety-device
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Interesting. The images seem to show it as larger than the claimed size (transceiver sized).
Not sure this is accurate though, "...A person’s chance of surviving an avalanche burial is 95% if they’re rescued within 15 minutes..." Is that assuming they survive the initial avy'?
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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| adithorp wrote: |
Not sure this is accurate though, "...A person’s chance of surviving an avalanche burial is 95% if they’re rescued within 15 minutes..." Is that assuming they survive the initial avy'? |
Yes. It's what I've always been taught, although I would have perhaps misremembered the figure as 90%, and then down to 25% after 45 minutes. The absolute numbers aren't so important though, just that of those who survive the trauma, 70-odd percent will die from asphyxia within that time.
This isn't the first device aimed at this issue, and indeed the additional airspace created by a deflating airbag was always recognised as helping with this. The issue I have with this one is that it's drawing air "...from outside of the pack, from the surrounding snow...". How much air can be pulled through rock-solid avalanche debris, I wonder? I guess if it's used in conjunction with an airbag it would help some.
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You need to Login to know who's really who.
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I guess dual function avi' packs is possible. I wonder if battery/fan packs could be designed to do both from the one system?
I'm speculating more on the engineering/design rather than on the effectivness
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Hmm. I can't remember what's actually in my cylinder, but it could well be nitrogen not oxygen. But those electric packs work with the same kind of approach, although they "store the air in the bag" before they're actually buried. Plus you'd have to have the gag in, which most people won't most of the time. I wasn't an Avalung fan, but they did build those into packs too... they were fashionable for a while, typically with the merchant banker crowd, whose logic I felt was "money is irrelevant, it can hardly make me less safe, let's have one". They stopped using those. I'm a little sceptical.
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You'll need to Register first of course.
You'll need to Register first of course.
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| phil_w wrote: |
| Hmm. I can't remember what's actually in my cylinder, but it could well be nitrogen not oxygen. |
CO2 in most of them, I think, but apparently the inflation uses a venturi that sucks a lot of air through, so the contents of the inflated bag is still relatively low in CO2. Not sure if that's true for all, but I believe it's how my first-gen SnowPulse works, so I imagine that later ones probably do similar, but better.
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| Chaletbeauroc wrote: |
This isn't the first device aimed at this issue, and indeed the additional airspace created by a deflating airbag was always recognised as helping with this. The issue I have with this one is that it's drawing air "...from outside of the pack, from the surrounding snow...". How much air can be pulled through rock-solid avalanche debris, I wonder? I guess if it's used in conjunction with an airbag it would help some. |
That was the principle that the avalung worked on and there were a few videos of test burials etc where it seemed to work. It seemed like the consensus was that flotation packs are generally a better solution except in heavily treed areas where keeping you on the surface increases the chance of trauma. Also the avalungs do seem potentially useful for tree well incidents
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| Chaletbeauroc wrote: |
| phil_w wrote: |
| Hmm. I can't remember what's actually in my cylinder, but it could well be nitrogen not oxygen. |
CO2 in most of them, I think, but apparently the inflation uses a venturi that sucks a lot of air through, so the contents of the inflated bag is still relatively low in CO2. Not sure if that's true for all, but I believe it's how my first-gen SnowPulse works, so I imagine that later ones probably do similar, but better. |
You are correct, all the cylinder packs use the venturi effect, so if the inflation of the bag is restricted in any way during inflation, you only get a partial inflation. One of the biggest advantages of the fan packs is that they aren't one shot and done devices, they keep pumping air so any temporary restriction can be over come (accept of course a really badly packed/fitted pack with the zips effectly constrained).
As for the gas used, BCA/Snowpulse use air, Alpride use an Argon/CO2 mix, ABS and most others use Nitrogen.
Last edited by After all it is free  on Thu 10-11-22 14:02; edited 2 times in total
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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@phil_w, avi' bags, like the Scott elec/fan one, don't "store air". It just uses a fan, powered from a super capacitor to inflate the bag.
What I was thinking was could that fan then be dual purpose and feed air through the shoulder strap like this device afterwards. No gag involved.
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Well when the bag is inflated... it acts as a storage reservoir for at least some air, in my humble opinion. Inflated bags are pretty big and protect your head by being around that area, so you have a reservoir of air right there. I think they even boast about it in their advertising. QED.
The point about the repeated cycle of the electric bags also seems... to make an additional device to do the same thing a bit superflous.
Oh yes - my own gas bag uses a venturi valve, so the nitrogen sucks in lots of air.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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*Also the avalungs do seem potentially useful for tree well incidents*
The thought of a tree well incident give me the heebie jeebies.
*How much air can be pulled through rock-solid avalanche debris*
I’d always understood that a fair amount of oxygen can be drawn thru snowpack, but your breathing slowly creates an impenetrable ice layer even if you’ve managed to make room in front of your face.
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