Avalanche Flotation safety device prototypes

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Originally Posted by jtwassoc

The upside to doing this is that people could get a feel for the device and know what it looks like and how it inflates so that they would not be seeing this for the first time inside an avalanche.

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It's an interesting conundrum: as a possible user I know that I would feel MUCH more confident that the device will work when needed (anti-jinx!) if I had tried it at least once before.

On the other hand, it makes sense that it must be professionally packaged at the factory before use.

It would be hard for me to trust that something I have been carrying around for years and never seen deploy will actually work in that split second it is needed.

This is more of a comment on my psychology than on the merits of your device...

Edited to say that I guess I do trust airbags in my car to work after years of inaction, so maybe this is the same. But I just realized that I never thought about the airbags in my car before: it's not like I have to remember to bring the airbag with me every time I drive somewhere...

The problem with an inflation device is making sure that the compressed gas hasn’t leaked out. This isn’t a problem with sealed CO2 bottles as they are welded shut. That was one of the great things about using CO2, it was readily available at a “reasonable” price in a sealed bottle. Not so compressed air or nitrogen. Why compressed air instead of CO2? Eventually we want to vent the compressed air into the air cavity created by the lift bag and the user (by using your hands to create an air pocket as the avalanche slows). Now we are compressing our own air here in the lab to 3000 pounds per square inch. The CO2 bottles were at 800 PSI. The compressed CO2 was in liquid form and the compressed air we are using now is in gaseous form. Now we are relying on a gasket and a big metal cylinder head to contain the gas. Gaskets rot out eventually and the gas escapes. A possible solution might be a gas leak indicator like you find on fire extinguishers.

Unlike the European flotation systems, we are building a one use device. We figure you survive an avalanche with the device it’s time to retire that device. The stress put on a nylon lift bag by a large slide is extreme, and in our opinion inflated lift bags should only be used in one avalanche only. Even the stress put on the nylon welds by the expanding gas can be impressive, and continued inflation of a lift bag worries us.

Here are some pics:

Thirty thousand dollars worth of parts.....

http://www.tetongravity.com/forums/a...7&d=1166198655

Venturi valve welded to nylon lift bag.......

http://www.tetongravity.com/forums/a...8&d=1166198669

Entire nylon lift bag. The bag is 100 liters or 3.5 cubic feet in size....

http://www.tetongravity.com/forums/a...9&d=1166198679

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Originally Posted by jtwassoc

we are building a one use device. We figure you survive an avalanche with the device it’s time to retire that device. The stress put on a nylon lift bag by a large slide is extreme, and in our opinion inflated lift bags should only be used in one avalanche only. Even the stress put on the nylon welds by the expanding gas can be impressive, and continued inflation of a lift bag worries us.

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Huh, hadn't thought of the stress per usage - makes sense.

I applaud you for using air instead of CO2. I always wondered what would happen if someone pierced a european system bag full of 5L of CO2 with a tree, rock, ski, pole, (or rescuer probe) what would happen if the bag leaked. I'd assume that asphyxia would occur very quickly with the CO2 displacing O2 in the local snowpack for the victim until the rescuer could dig them out.

Three questions...

QUESTION 1. Have you considered using nitrox fills instead of air? 3000psi fills can be had cheaply from your local SCUBA shop. All you need is an adaptor. EAN50 would be nice (50%O2).

Since you intend to bleed the bag off, EAN would be beneficial to the victim to have a gas pocket of enriched O2 air versus normal air for MANY reasons. Higher ambient %O2 means:

1. less hypothermia - higher FiO2 means higher SaO2% especially at altitude: slower respiratory rate which means slower core cooling of the victim ( http://jap.physiology.org/cgi/content/full/96/4/1365 )
2. less stress - on an injured victim, especially at altitude (too many physiological reasons to list)
3. longer breathing time - it would take a much longer time for expired CO2 to cause displacement asphyxia than with normal air.

(great marketing point too ;))

QUESTION 2: CF reinforced cylinders Have you considered using small CF cylinders for gas storage? They seem to be available for paint ball players in small cylinders that are rated to 5000psi. Using those would surely decrease system weight and size?

QUESTION 3: Psychology of replacable cartriges Going off of Aleks points... don't you think that the ability to pull a ripcord and restore the system for $75 with a new cannister makes people more likely to pull the cord without hesitation than if it will cost $300-$400 to replace the entire system?

EDIT: On further inspection, replacement cannisters cost $150 for the european system.

We are looking at all gases, including mixes such as the ones you mention being common in SCUBA shops. Right now we are going with compressed air as we fill it right here in the lab (see pic below). Every move we make is cost sensitive as we feel if we get over the cost of a beacon people will not use it. We are still playing around with the inflation gas, and a mix is not out of the question.

As far as pulling the rip-cord goes, it would be more than $75 to replace the cylinder and the valve parts, but not too much more. The whole issue of providing someone with a zero maintenance one time use only device, as opposed to a user rechargeable multi-use system is under a lot of discussion here in the lab. The more serious mountain guide types in our group are all techie gear-heads and love to buy the finest equipment and tear it apart to see how it works. They all want to produce a rechargeable system. But the less intense back country people in our group want the zero maintenance one shot device. Maybe the answer is a guide model that is rechargeable and a weekend warrior model that is not.

http://www.tetongravity.com/forums/a...4&d=1166217287

I'm stoked you guys are working with price in mind.

It would be nice to see this technology become commonplace in this country.

Here's some pics of one of the first prototypes from a few months back. The new devices will be a tad smaller, maybe a bigger rip cord as well...

http://www.tetongravity.com/forums/a...1&d=1166888810

http://www.tetongravity.com/forums/a...2&d=1166888820

http://www.tetongravity.com/forums/a...3&d=1166888830

http://www.tetongravity.com/forums/a...4&d=1166888839

http://www.tetongravity.com/forums/a...5&d=1166888847

A couple things, first off, we are looking for a beefier waist cord. One that won't tighten up and maybe cut you in half in a giant slide. Last year a similar "harness" was used in a major league class three avalanche that slid most of a mile, and when the test dummy became stuck against a large pine tree the avalanche put so much stress on the tether that it completely sliced through the 400 deneir nylon lift bag. Extreme forces are at work in an avalanche so we don't want the attachment point for the lift bag to the user to be dangerous in any way.

Also, if you have emailed us looking to get on the prototype testing list and have not received a reply, don't give up. We are waiting to see how many people submit their paperwork, and not everyone has done this so there may be openings. We will contact everyone who has emailed us one way or the other. Thanks for your patience........

Good stuff. I ride 50+days in the BC every year and blah blah blah.

Whatever you come up with, I hope it doesn't cost $800 like the one at our shop.

This is awesome to read about. Do you have any videos from the tests with the dummy? I'd like to see this thing in action!

I'm a little skeptical as I don't see any open beers sitting around your shop.
The hammer sitting next to $30,000 venturi valves is reassuring though: "Dang it, looks like this one needs some 'adjustment', I'll 'fix it', I'm mechanical.";)

In all seriousness though, your product is impressively small and looks pretty light weight. I've been following your thread in the slide zone and the results are very promising. Those slides you guys created are very impressive, even if many of them were too big for your purposes.:eek:

I'm prolly out for most of the season myself, otherwise you'd have heard from me sooner. I think a rechargeable version might be nice for pros. I know on my patrol, you could count on taking a couple of rides per year, hopefully small. But you wouldn't want to be discouraged from pulling the ripcord. Even if the device had to be sent back for repacking, inspection, etc.

I see what you mean about the waist belt too. I think integrating a climbing harness with a more positive buckle system could be an idea.

Thanks for all your hard work, keep it up.:yourock:

edit: It would be cool to see some of the component parts before packing, like how small your bottle is.

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Originally Posted by foxy

The hammer sitting next to $30,000 venturi valves is reassuring though: "Dang it, looks like this one needs some 'adjustment', I'll 'fix it', I'm mechanical.";)

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ha, I was thinking along the same lines, pretty funny.

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Originally Posted by Summit

I applaud you for using air instead of CO2. I always wondered what would happen if someone pierced a european system bag full of 5L of CO2 with a tree, rock, ski, pole, (or rescuer probe) what would happen if the bag leaked. I'd assume that asphyxia would occur very quickly with the CO2 displacing O2 in the local snowpack for the victim until the rescuer could dig them out.

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The ABS data sheet indicates they use N2. I can't be bothered digging up the bottle to see if that's confirmed on there. I'm guessing pure N2 isn't as big a problem as CO2 if it leaked considering air is 78% N2?

Actually, maybe they should replace the N2 with N20. At least you'd be happy and relaxed down there if it leaked :D.

N2 can still displace the O2 causing hypoxia or asphyxia. However, it won't cause hypercapnia.

Waiting to hear about the first ripcord that got deployed when somebody falls on it or snags it on something while skinning. :D

I also can't wait until we get the first "So my buddy says, 'What the hell is this thing?' and then he pulled the ripcord... in the parking lot." report. :Dx2

Impressively small and compact. This thing could revolutionize ski touring in North America.

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Originally Posted by phUnk

Waiting to hear about the first ripcord that got deployed when somebody falls on it or snags it on something while skinning. :D

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Yep, that occurred to me as well. Obviously it's still a prototype but some kind of trigger protection would be useful. E.g. the ABS trigger has a velcro strap around it. If the velcro is tight it's difficult to trigger. You're supposed to loosen the velcro before entering avalanche terrain which allows the trigger to have a few inches of space for easy triggering.

I would think a trigger safety would be vital. Perhaps we just cannot see it in the picture.

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Originally Posted by phUnk

I also can't wait until we get the first "So my buddy says, 'What the hell is this thing?' and then he pulled the ripcord... in the parking lot." report. :Dx2

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Better there than on a 5-ft wide summit platform just before the summit photo. :eek:

Likin' the size factor. ~12" x 4" x 6"?

Re: Venturi valve and total inflation.

Just a thought on this but......

my guess would be when one pulls the rip cord they are very likely to be sitting slightly due to the slide taking their feet away from them, or engulfed in some cloud of snow. IE Slide has already occured.

How will this effect the total inflation capacity of the bag?

Has this been tested when sitting slightly, or sliding down while in a hip check position in powder snow and pulling the rip cord?

Great idea on the device though.

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Originally Posted by jtwassoc

Update for anyone waiting on a flotation device.

The venturi valves are the most time consuming manufacturing process and the valves are now being machined. The venturi valve is a critical part of the device and here's why. The heaviest part of the device is the steel pressure bottle that holds the compressed air/nitrogen. The bigger the bottle, the greater the weight. We need 3 cubic feet of gas to inflate the lifting bag that will float you to the surface of the moving avalanche. A pressure bottle holding 3 cubic feet of gas is more than you would want to carry, so a venturi valve is used to multiply the amount of gas produced when you pull the rip-cord. The venturi is attached to the outside skin of the lift bag, and a high pressure gas hose runs from the pressure bottle to the venturi. There are small valves open to the outside air on the top of the venturi, and when the rushing gas from the bottle runs through the venturi it draws in a huge amount of outside air.

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Paperwork sent in. What a nice light small compact looking system.

Gotta love a hammer. Threw it in there for size comparison.....

As far as accidents go, the best ever was when a University of Minnesota student (we work with U of M students on various projects) decided to take a wrench and remove the cylinder head off a live 20 cubic foot CO2 bottle. He was sitting on a chair with the bottle held between his legs to hold it. He said the bottle hit the floor and started to spin so fast "it appeared to dissappear", then it touched one of the chair legs, straightened out and took off like a jet engine. First stop, a 12 pack of grape pop near a wall. When we first got to the lab (this all happened at night during finals week cramming) we thought someone had been killed as there was a huge spray of what we thought was blood all over the wall. Anyway, the bottle sailed around the lab for 30 seconds creating all kinds of mayhem before finally burying itself in a wall. The mortgage company all night phone telemarketers next door ran out of the building because they said they thought they heard a train jump the tracks and smash through the building. Quite loud apparently.

We also make flotation devices for rescue types attempting water and ice emergencies, and State Troopers are famous for accidently pulling the rip cord. "Geez, I was getting the thing out of my trunk and the rip cord snagged on the barrel of my assault rifle...." etc.

The problem of an accidental inflation is a tough one. We have tried models with velcro covering the rip cord, but we don't like asking the user to remember to expose the rip cord before each run. In the 50 or so recorded uses of avalanche lift bag technology in Europe, 5 people died when their lift bags did not inflate. It is possible they never pulled the rip cord. We don't know why this happened, but covering the rip cord gives us the creeps.

Found some pics from last years test showing how a tether can shred through some pretty tough nylon like a hot knife through butter....

http://www.tetongravity.com/forums/a...3&d=1166978388

http://www.tetongravity.com/forums/a...4&d=1166978398

........but then again this was a MONSTER slide that buried our test dummy 8 feet below where this dude is standing (check out how far up the tree the avalanche left its mark). When we went back to clean up parts this summer we found that the dummy was stopped 8 feet up in the tree.

http://www.tetongravity.com/forums/a...5&d=1166978756

However....... in three class 2 slides (can't destroy a house) the year before we had pretty good luck floating the dummy.

After slide 1:

http://www.tetongravity.com/forums/a...6&d=1166978933

After slide 2:

http://www.tetongravity.com/forums/a...7&d=1166978941

After slide 3:

http://www.tetongravity.com/forums/a...8&d=1166978951

Note: this last pic is after we dug him out.........

Adam, post test avalanche three, Revelstoke, British Columbia 2005........

http://www.tetongravity.com/forums/a...9&d=1166978961

Update for anyone waiting for a device or on the waiting list.

The devices are being manufactured presently. We are hoping to ship out the devices by late January, but don't be surprised if we are late. If you have received your legal waiver you need to sign it and mail it to us. If you have contacted us but haven't received a waiver you are on the short waiting list.

The devices cannot be taken on an airplane. It is legal, but convincing airport security of that is a 50-50 deal at best. We have missed 1/2 of our flights trying to travel by air with the device. If you cannot drive to the mountains you can't help us with the testing.

Thanks for your patience.

More pictures soon.......

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Originally Posted by Summit

N2 can still displace the O2 causing hypoxia or asphyxia. However, it won't cause hypercapnia.

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The ABS bags also use venturi valves.

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Originally Posted by jtwassoc

The devices cannot be taken on an airplane. It is legal, but convincing airport security of that is a 50-50 deal at best. We have missed 1/2 of our flights trying to travel by air with the device. If you cannot drive to the mountains you can't help us with the testing.

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Based on your similar post in another thread I decided against travelling with my ABS cylinder and trigger in this day and age. Unfortunately I also found out that postal services won't receive/transport Dangerous Goods (which any compressed gas is classified as). Instead I triggered the airbags (fun!) and sent the empty cylinder and discharged trigger with the signed declaration that they aren't Dangerous Goods and clearly writing they are empty/discharged. Luckily I'm going to be near shops that'll exchange full cylinders/triggers.

I feel that, as previously mentioned, it would be an advantage for your product to be refillable and able to use SCUBA gases (e.g. compressed air or nitrox). The ABS system is only supposed to be refilled by the manufacturer and it's costly to get done. If a dive shop could do fill your cylinders for the standard SCUBA refill price (a few $$) you'd have a huge network of places that could do it and open up a market for air travellers. Not only international, but people who want to take the device on flights within the U.S. Surely most decent-sized cities that people would fly into would have at least one SCUBA shop capable of refills even if they weren't near an ocean. That way people could post them ahead (even directly to a dive shop) and pick them up or get them filled at their destination.

My airline is currently trying to obtain permission for me to travel with the cylinder/trigger anyway through their head security department. Maybe I'll try it on the way home.

Wow. Wish I'd opened this thread a while back and gotten in on the test (though a steady stream of visitors has had me skiing inbounds for over a month, so maybe I'm not the best subject this year). One thing I can't tell from the pictures - does the hipbelt mount with the bag towards the back (user's ass)? That is what I initially assumed, but it looks like your dummy has the inflated bag on his stomach. Either way, I assume that the hipbelt plus a back pack would be awkward. How do you guys deal with that problem? One turn off for me on the original avalungs - I thought that the outtake vents on the vestwere on your back and thus you were not supposed to wear a pack with it.
Looks cool. Best of luck with it.

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Originally Posted by Toby

The ABS bags also use venturi valves.

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Wow I feel like and idiot. I've known this but never put 2 and 2 together.

So the next question is what percent of the final fill comes from the ambient air via venturi action?

(and your others are very good too i think)

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Originally Posted by Summit

Wow I feel like and idiot. I've known this but never put 2 and 2 together.

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Yeah, it was sort of in the back of mind but I got sidetracked and didn't continue that train of thought.

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Originally Posted by Summit

So the next question is what percent of the final fill comes from the ambient air via venturi action?

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2/3 according to a downloaded pdf (in German) that I found on http://www.abs-lawinenairbag.de. I doubt the direct link works but if you follow the "Service" then "Downloads" links it's in the "Das ABS Airbag Prinzip" pdf. And probably elsewhere.

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Originally Posted by Summit

(and your others are very good too i think)

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You talking about the air travel/refill point? It's a major PITA not being able to travel with it. Living about 2500 miles from the nearest ski hills and half a world away from any ski hill I'd consider actually skiing at means I have to travel. I was going to take the cylinder but jtwassoc scared me enough with his security comments. I'm travelling with a wife and 3 small kids and the last thing I need is to miss flights and be hauled through security. If I was alone I might risk it. I'm unsure whether the postal service will complain about the cylinder, but I wrote "empty gas cylinder" and clearly highlighted the "empty". The worry is that if the postal service says it's a Dangerous Good (i.e. compressed gas), they will destroy it and charge me the cost of destroying it. I can imagine they'd want to follow some bullshit safety procedures and charge a lot to do that, plus I'd lose my cylinder which is an extra cost. I'm also worried about where I sent it - Toby c/o the post office in the town I'm going. I didn't forewarn them I'm doing that so I hope some little backwater Austrian town holds it for a while until I get there. What pisses me off is I can't send compressed nitrogen, but I can send biohazardous material legally via post :rolleyes2.

It cost me - ~US$20 postage to send the thing and IIRC will cost about $50 for a refill. If a dive shop could refill it for $5 I'd be much happier about the whole thing. Even better if a service station could do it, although I think the pressures handled by tyre valves and compressors are probably orders of magnitude less than those necessary for the airbag system. Not to mention people losing lives and limbs messing with those pressures filling cylinders themselves :). But yeah, design it so we can screw some Schrader attachment on the cylinder and fill it up at a service station. Just get an attendant to do it ;).

The problems with the refilling the gas cylinders are tough ones for us. First off the added cost to the user. It doesn't sound like much, but the added hardware required for a refill would add cost to the device. We think cost is one of the major reasons people do not commonly use avalanche flotation devices. We need to carve every penny we can off the manufacturing costs in order to make it affordable for the user, and to build more features into the device than we have in it right now would drive up the cost of building it. A second problem we have is the stress involved in inflating the device, not to mention the stress involved in putting it through an avalanche. There are many of us here in the lab that feel that one inflation is all a lift bag should be put through. True, we reinflate the devices dozens and dozens of times for testing purposes here in Lakeville, and we never have them burst, but we're not riding the thing down a mountain in a serious slide hoping it won't pop because of a seam weakened from repeated inflations either. So the question is, if the device is cheap enough to purchase, can the user live with the fact that it is a one shot deal and that once inflated it's non-reusable?

As far as the diffriculty with airline travel goes, we think that once the devices start showing up by the hundreds at airports, the security people will become used to the fact that it is legal to fly with avalanche flotation devices and it will slowly become an acceptable practice.

We are playing around with the placement of the device on the user's body, and our original design swings the lift bag up and in front of the user's chest, as you see in the crash dummy test avalanche pics. In a few weeks in British Columbia we will be testing the rear mounted fanny pack design, among other things. There is a lot of discussion as to where the lift bag should end up in relation to the user's body after the slide has stopped moving.

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Originally Posted by jtwassoc

We think cost is one of the major reasons people do not commonly use avalanche flotation devices.

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For sure, but so is convenience. If it's only usable by people who can drive to the mountain you're limiting your target market.

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Originally Posted by jtwassoc

A second problem we have is the stress involved in inflating the device ... we're not riding the thing down a mountain in a serious slide hoping it won't pop because of a seam weakened from repeated inflations either.

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I like that the ABS system has two independent bags. If one pops, the other still works. Maybe you could design two (or more) independent chambers, like inflatable boats commonly have multiple chambers?

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Originally Posted by jtwassoc

As far as the diffriculty with airline travel goes, we think that once the devices start showing up by the hundreds at airports, the security people will become used to the fact that it is legal to fly with avalanche flotation devices and it will slowly become an acceptable practice.

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Early adopters beware :D. Unfortunately in Australia any ski equipment is uncommon so I doubt security would ever become used to them. They'd just see a Dangerous Good. Same in lots of other countries.

Quote:

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Originally Posted by jtwassoc

We are playing around with the placement of the device on the user's body ... In a few weeks in British Columbia we will be testing the rear mounted fanny pack design, among other things. There is a lot of discussion as to where the lift bag should end up in relation to the user's body after the slide has stopped moving.

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I can't see how the rear mounted design would work since most backcountry users (your primary market) will have a pack the size and shape of which you won't be able to predict. And what if they were bootpacking and the slope slid (unlikely scenario considering when and where bootpacking is required but I'm playing devil's advocate)? Skis/board on the pack extending down behind the knees would restrict the inflation space. I'm pretty happy with the ABS side-of-the-pack design now I'm getting used to it. I liked your front fanny pack design, as long as there's no chance of it smothering your face. If you were going with a rear mounted design, I'd prefer two bags diagonally out behind your kidneys, although I guess that'd be hard to tether strongly enough to the fanny pack.

I liked your earlier idea of the basic one-shot model and the pro reinflatable model. Basic model for locals, pro for travellers. It works to an extent with beacons, right? There are basic no-frills models and there are pro models with the pro ones attracting quite a lot of attention on here (which would also be a significant target market for your hypothetical pro model).

And before I forget, another thought: let's forget the litigation issue in the U.S. and pretend there are no liabilities - what about if you sold a version with no cylinder? Then have outlets (outdoor shops, guide businesses, cat/heliskiing ops) with full cylinders that customers can rent for e.g. $5 a day or less for long term. You supply the cylinders to the outlets so they have no upfront costs (makes them more willing to supply them). You split the profit 50/50 with them. That way, you have an ongoing revenue stream. Customers pay a deposit that's forfeited if they use the gas. Outlets measure by visual inspection and/or weighing like with the ABS cylinders. Periodically (every year?) outlets send in cylinders to you for inspection/replacement. Periodically (every couple of years?) clients are supposed to send in their fanny pack to get inspected by you otherwise they forfeit various performance of product guarantees. Etc.

If I were able to travel with peace of mind with no cylinder and know I could pick one up temporarily at my destination at low cost, that'd rule.

Here's another update for anyone waiting on an avalanche flotation device.

The devices are looking pretty good. It's turning into a "fairly" small fanny pack type prototype. We are pretty happy with the harness, and it seems to be somewhat comfortable. At least as comfortable as 3 pounds of gear hanging on your fanny could be. An average sized backpack (Dakine Heli-Pro) with probe, shovel, etc. seems to be workable with the device on.

But all that comfort and cozy self congratulatory feeling is while wearing the thing standing around in a nice warm, dry 70 degree lab with a large Caribou Coffee mocha in one hand. How it will work out in the wilderness we will find out the week after next in British Columbia when we field test the devices. If everything works out in the mountains we will give the thumbs up to our shipping department and those of you we have promised devices to will get them the first or second week of February.

The week in Revelstoke will be spent doing two things:

One, wearing the device ourselves and see how it performs while skiing, hopping in and out of helicoptors, having lunch, chatting up good looking girls in the bars, etc.

Two, we'll be inflating the devices attached to 200 pound crash test dummies and rolling class 2 avalanches over them to test the durability and the flotative qualities of the prototypes. That's assuming Mother Nature cooperates and we are able to fly. We will report all testing withs pics and comments when we're finished.

Thanks for your patience...........

I don´t do múch now but had 7 weeks often a year pro skiing - but not much in backcountry :Tell me if you sell it or wholesale it then I am interested.
Did you notice the many death of people in float vest that had no neck cover as it does not keep head out of water - Why not make it so head stays out of snow ? bf

This is a good question, as obviously we want the head of the victim out of the snow. One problem is correctly positioning the inflated lift bag on the person so that the head is oriented to the surface of the avalanche. We believe the best place to keep the device on the person is the fanny pack on the hip. So we are trying to design something that inflates towards the upper torso. It is a bit of a challenge to bring the inflating device around to the front of the victim in an avalanche. It is less of a problem to inflate the lift bag up the back of a victim.

In many avalanche tests the lift bag ALWAYS seeks the surface and is only partially buried after the slide stops. In all of our tests we were never able to bury an inflated lift bag under an avalanche, it’s impossible. Imagine trying to stop a three foot bubble of air under water from reaching the surface. As a result of this tremendous floating force the victim will be pulled to the surface of the avalanche by the lift bag, and whichever side of the person is closest to the lift bag will be closest to the surface. So if your chest is closest to the lift bag you will be partially buried face up. If your back is closest to the lift bag you will be partially buried face down. There is a lot of debate as to which way you want to be partially buried, face up or face down.

Another notable thing we have found in our avalanche tests is that victims (crash test dummies) are always partially buried horizontal to the surface of the snow. We never find the dummies head up or head down. They are always positioned so that the hips and the head are the same distance from the surface. This distance is usually 6 to 8 inches from the surface. We always find that either the chest or back is partially exposed or closest to the surface. The completely exposed parts of the dummies so far have been either a hand or a part of the torso.

To completely expose the victim’s head on the surface would require a lift bag that would inflate around the head, and these designs are seriously expensive to manufacture and already patented as well. We have to stay within the design boundaries of our patent application and also build an affordable device, so we feel the fanny pack design is the best course of action……..

Hopefully this is a link to a video of the deployment of a head placed lift bag system:

http://www.avalanche-research.com/si...E.flv&logID=11

Its called the PUFF system...........

Testing week has finally arrived and tomorrow morning Adam and Eve start the long drive to British Columbia. There should be avalanches rolling over them by Wednesday.

http://www.tetongravity.com/forums/a...1&d=1169850024

Here is the finished prototype device.............

http://www.tetongravity.com/forums/a...2&d=1169850101

(Just a hair over three pounds.)

You should develop a float that stows on a snowboard to combat the anchor effect. Then send me royalties. cheers.

Testing is complete in Revelstoke, British Columbia. We are back in the Squaw Valley, California office examining our film and data. Bottom line, lift bags tend to become completely exposed on top of the avalanche after it has stopped moving. You definately want to be attached to a lift bag if you find yourself in an avalanche. Lift bags work.

Very cool pictures to come.......