Hypothermia and Immersion Hypothermia are both serious killers of people in the outdoors each year. Most cases of hypothermia happen in 50 degree F weather and are preventable- dress properly (no cotton!), stay hydrated, and do something about it when you get wet or begin losing dexterity such as build a fire & shelter, get back to the vehicle, or into the sleeping bag. A good hypothermia recipe is to have a cup of hot chocolate with a tablespoon of butter and I always carry this solution in a thermos when on the winter trail.
Keep in mind that the statistics bear out that the classic "survivor" lost in the wilds each year is injured and hypothermic.
Immersion Hypothermia is a real killer and you only have a limited amount of time on your hands. The best info comes from this U of Toronto Professor who has studied it the most and is on YouTube. Pass this vid around to those who spend time playing ice hockey, ice-fishing, or traveling the wilds in winter. It can be a lifesaver to know- http://www.youtube.com/watch?v=ysnKtuUTt8k
Another test I do with my students on winter survival courses is to have them place their hands (minus gloves) in the snow for a count of 60 seconds. After this, they must get a fire going using their matches, lighter, or spark rod. With a loss of dexterity, the spark-rod wins out as it involves gross-motor movement compared to the lighter and matches. Try this test in the backyard next snowfall and see how your firemaking gear holds up when the hands are numb.
Cottonballs smeared with vaseline and used for tinder is the other half of the picture in successfully starting a fire when the forest is buried in snow.
Tony Nester
Ancient Pathways, LLC
http://www.apathways.com