Snow is a great insulator, actually.

In the small space you’ve got to yourself, your body heat can make a pretty comfortable cocoon. It’s actually recommended that if you find yourself stranded in the wilderness in winter, that you make yourself a little snow cave for shelter.

The crush isn’t as much of a concern, because that happens right at the beginning. Once you’re crushed by an avalanche, you’re not doing much more worrying.

The main concern is CO2 levels in your little cavity. Each breath you take makes the aid you’re breathing a bit more toxic.