You couldn't pay me to ski or snowboard without a backpack that has AvaLung built into it.
(If you're not familiar with AvaLung. It's essentially a breathing tube built into the strap of a pack, and vents your air out the back of the pack and intakes oxygen, as best possible, from the front. Increases your odds. As best possible.)
What about an ABS Bag? I've thought about one for snowmobiling.