In the summer I had three packs all set-up depending on the probability of having to overnight in the event of an accident. Low-High or moderate.
But for winter there is really only one option, and that is plan for High risk. In the summer one might crawl out if they broke a leg, but your not going to crawl out through five feet of snow.
Almost everything I do is solo hiking or snowshoeing. Having almost enough sleeping bag @ -16F below zero would get me just as dead as having NO sleeping bag. So I have cut some large sheets of 6 mill vis-queen to replace the bulk of a tent, plus trying to set-up a tent on snow if injured would be hard. So I plan to keep it simple, vis-queen, two light weight sleeping bags, plus what ever I can add up to about 35 pounds.
I prefer external frame packs, but this kit will also double as a survival kit for the snow machine, and it demands no external frame which would snag on tree limbs & Alders.
So What is in your winter survival kit......? Do you even have a winter survival kit....?