One safety device that can help a potential avalanche victim improve the chances for survival is an ABS-type balloon that can be inflated prior to or while being engulfed in the moving avalanche. It increases the victim's buoyancy in the fluid and often deposits him or her at or near the top snow layers when everything stops.
But not always. And you can be near the surface and still be too deep or disoriented to rescue yourself, in which case you'll still die if you're not rescued quickly (ca. 50% mortality at 30 minutes).
The idea is a similar balloon that is (much?) larger and into which compressed helium is rapidly released from a canister, so that the potential victim is lifted vertically clear of the avalanche. Ideally you'd deploy it before being involved in the flowing snow, but even if you get caught, it would at least do as well as the conventional balloons, and would still have a better chance of pulling you entirely clear.
Once free of the avalanche, of course, you'd face the peril of finding a safe place to land (a release valve would allow you some control over descent) and hoping to avoid disastrous collisions with trees or rocks. But I think these risks would be less dangerous than burial in the snow.-- beauxeault, Jan 03 2002 Balloonachute http://www.halfbake.../idea/BalloonachuteAn hb device that helps with the landing problem. [beauxeault, May 24 2002, last modified Oct 04 2004] That would have to be a BIG backpack, but I'll pastrify you anyway.
I did a rough calculation and it would take a sphere of gaseous hydrogen 17.7 feet in diameter (5.4 meters) to lift a 200 lb weight.-- seal, Jan 03 2002 Baked, at least in that James Bond movie with Pierce Brosnan. His ski coat had a rip cord, he pulled it, it inflated into a large ball. //there, that's 4 times I've cried "baked" today//-- quarterbaker, Jan 03 2002 Why not just a balloon that lets you 'roll with the flow'? Hell, it could become an Olympic sport.-- phoenix, Jan 03 2002 I would thnk that theoretically a baloon a couple of metres across would do fine... once deflated it would leave a large whole in the snow behind you.-- CasaLoco, Jan 03 2002 You know those rolled-up noise-maker things you get for kids' parties that you blow into and air pressure forces them to unroll into a hollow cylinder with a loud tooting noise? Something like a big version of that attached to your jacket and inflated by a little gas cannister. It would go up through the snow and act like a flag, and you could breathe through it. Also the sound would attract rescuers.-- pottedstu, Jan 04 2002 ...learn something new every day...-- phoenix, Jan 04 2002 Maybe some combination of balloon (goes skyward), propulsive mechanism, and pocket warmer (melts snow to let it move) to get up through the snow to make an emergency signal like a buoy.-- joycee, Feb 19 2002 There are a bunch of rescue-balloon ideas here at the halfbakery, but this is probably the closest to what I had in mind, which is the rescue balloon in the movie Waterworld. Living on the coast exposes one to the danger of a tsunami; a rapidly-deployed balloon would give you a better chance of survival than anything else I can think of. As long as you only deploy it in such an emergency you would probably escape Larry Walters' fate. (You don't REALLY think he committed suicide do you?)-- jcomeau_ictx, Apr 19 2005 Acrylonitrile butadiene styrene? Antilock braking system? Ankaferd BloodStopper?
Or did you mean SRS, which can stand for supplemental restraint system (aka car airbags)?
Regarding avalanche balloons that are not buoyant in air: I think it would make the most sense to mount it at the top of the wearer's backpack. That way, it orients them upright enough due to differential buoyancy (like a life jacket). Car airbags also have the advantage that their gas generators are more compact and much safer than pressure vessels. On the other hand, if it's inflated with breathable air, the victim has something to breathe while they dig themselves out or wait for rescue.-- notexactly, Dec 03 2018 random, halfbakery