An item not mentioned in above lists that should be in any vehicle that might get disabled by weather or any other condition:

A DURABLE form of note paper, a reliable marker, and a clip or clamp you can use to SECURELY fasten a note where it will be visible outside the vehicle.

While the general rule is that you DO NOT LEAVE YOURE VEHICLE if it's disabled - ESPECIALLY IN SNOW - there might be a situation when it might be acceptable or even necessary to do so.

If you must leave the vehicle, it is essential that you be able to leave a conspicuous notice of what you think you're intending to do, and how you plan to do it. You should ideally leave one not outside the vehicle where it's visible from a distance, and a second note inside where it can't blow away.

Failure to do so means that your body won't be found until after the snow melts, which probably will be after resuscitation is possible.

Even if snowfall has stopped, the sun is out, and visibility is excellent, you may not be able to travel as far as you think, and if you're down in the snow even alittle wind drift can cover you and your tracks in a very short time. If you're down more than fifty feet from your vehicle it may be impossible for aid, even if it arrives in time, to find you, especially without very specific information about what direction youu started out and where you intended to go.

And always put your name on the note for identification purposes. It's the polite thing to do for those who find what the critters don't get rid of.

John