I saw a similar story on Discovery Channels "I Shouldn't Be Alive". It was a young married couple and their infant sun. They were driving through the mountains in a similar area and it started snowing heavily enough to lose track of the road. By time the snow stopped, they were miles from anything and there was no sign of the road they came in on (since they had been driving in the dark previously).

They did what most people would have done, which is to stay with the vehicle as long as possible, but they soon realized that nobody was looking for them and they weren't anywhere that they could be found. They walked for a day or two in attempt to find anyone that could help, but then the wife and child couldn't keep going. The husband had to make a decision to leave them holed up in a cave with what little supplies they had and continue to look for help. The only difference is that in this case, he managed to find help, was able to tell them where the cave was that his wife and child were in (and had the sense to mark a nearby tree with something brightly colored), and everyone survived, against all odds.

Now I guess the real thing to do to try to mitigate that sort of risk is to make sure somebody knows where you are going and how you are getting there before you leave. That way if you don't show up, they will know to look for you and more importantly WHERE to look for you. Doesn't help if you end up off the road or taking a different route, but it's better than nothing.

So if anyone is interested in a depressing documentary:

L.O.S.T. in the Snow (can I just say that I hate the automatic text replace of "l o s t"?)

The Survivors: James and Jennifer Stolpa
The Dilemma: Could you abandon your wife and baby in a snowstorm?

A U.S. Army private is driving to a family funeral with his wife and 4-month-old son. They get caught in a blizzard, and a simple wrong turn leads them deep into a frozen wilderness where their car gets stuck in a snowdrift. After surviving for days with no provisions they realize that there is little hope of rescue. They decide to abandon their vehicle and walk to find help. But in this unforgiving environment they are soon overcome by exhaustion and frostbite. The young family has to confront the real possibility that they are not going to survive. Should the father say goodbye to his wife and baby and try to make it out alone? Or should they stay together as a family – whatever the cost?