An AvaLung only increases your odds of not dying from suffocation if you are buried. Even with an AvaLung, if you are buried more than a meter or so, the weight of the snow pressing down on you is such that you cannot expand your chest to breathe. Sort of a boa constrictor effect. I helped with a body recovery last March at Hatch Peak where the skier was buried about 14 ft (4.25 meters) deep. An AvaLung would have done him no good whatsoever.

In the Pemberton incident, the skier was not buried, but died from trauma. Big slides are increadibly powerfull. Somewhere I have a photo I took in spring, after the snow had melted, of a place where one of our roads had been blocked by a slide. The guard rail is bent into a pretzel, and the guard rail posts are sheard off flush with the ground. A person caught in something like that will likely be killed outright, irrespective of whether they are buried or not.

The bottom line is that most avalanches are triggered by the victim, or someone in his/her group. While gear like beacons, AvaLungs, etc, increase your odds of survival, the best chance of survival is to not get caught to begin with.