sorry but I'm a midwestern'er and have only flown over mountains. I know zero about avalanches.
Does the skier deploy the bag???
I take it, it's designed to help keep them above the sliding snow to not get burried much like a life jacket/preserver???
There's a trigger type of mechanism that is inside a pocket on the back pack. When taking lines like this you pull the trigger out of the pocket in case you have to use it.
If you trigger something and are going down, pull the trigger thing and the bags deploy.
The way I understand it is basically it changes your weight to space ratio and your head area becomes very light for the size it's taking up and that part of your body floats on top of the snow.
However, the most videos I've seen of test and such with these being deployed, the entire dummy or person seems to always stay on top of the snow.
So apparently the way I understand it of just keeping your head area up high is being debunked and basically the majority of your body will float, if you're lucky