What the air bag does is actually two things. One thing is that it decreases density of a human, which is much higher than the one of the snow. (From 1,000 fg/m3 to about 400 kg/m3.) (Air Bag)
The second thing it does is make the skier become a bigger particle. This helps the victim stay on or close to the top of the moving snow. Because smaller pieces stay under the surface, like a human by them self with out an air bag, would be under the surface the whole and probably never surfacing. The avalanche seams to sort the big pieces and put them on top, and the air bag makes the person bigger, it keeps them on the top. (Air Bag)
During 1991-1997 12 people with air bags survived the accident. But you can not be certain you will be completely buried. In cases of the person being buried the balloon remains on top of the surface making it easier to find the person.
In conclusion avalanches can happen to any one who takes the risk and there are many factors of witch can cause them to happen. The victim is one of the main causes that the avalanche starts in the first place. So when going hiking or skiing check the factors. Look at the weather, get an extended forecast, as some locals about the avalanche activity on that mountain this year. Check the snow layers, and just don’t think it can’t happen to you. Remember avalanches can occur where there is sufficient angle and enough snow to slide.
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