It seems like a few people die this way every winter in the Canadian Rockies when they get trapped in a snowstorm on a road trip.
I seem to recall another family getting lost in this area last year..in those back mountain roads near Gold Beach, OR. In that case, they were in a big camper, had some food and could stay fairly warm. Several people were in the camper. I forgot how they were rescued but after the feel-good stories in the media, it turned out that one of the snowbound fellows was wanted by the police.