Hypothermia

"Never such a blizzard before"
- from the song Baby it's cold outside

Hypothermia describes the rapid, progressive mental and physical collapse caused by the chilling of the inner core of the human body. It is the number one killer of outdoor recreationalists who simply can't believe that temperatures between 30 and 50 degrees can be dangerous. When dry and covered you might survive 30 degree air. But swimming in 50 degree water can be deadly and when your clothes are wet in fifty degrees air, the cold water running down your neck and legs quickly robs body heat. A blowing wind will go through and under wet clothes, evaporating water on your skin, causing a refrigeration effect.

I'm quite impressed by the site http://www.adventuresportsonline.com/skihypo.htm which provided the hypothermia information above. It also charts comparing water temperature to survival times, signs of hypothermia, what to do, and more.

From eMedicineHealth I learned that Hypothermia has been a military problem ever since Hannibal lost nearly half of his troops while crossing the Pyrenees Alps in 218 B.C. It has continued to plague military campaigns through both world wars and the Korean War.

Bottom Line

Uncontrollable or violent shivering is a warning sign of early stage hypothermia. Shivering can double heat generation for a few hours. But eventually fatigue sets in, and the body exhausts its fuel stores. As your core body temperature drops, cold reaches the brain depriving you of good judgement and reasoning power. You will not realize this is happening. You will lose control of your hands, then your body, and eventually die.

Seek help immediately while you still have the energy, the muscle coordination, and the common sense to reach help. However if you're lost don't wander at random hoping to be rescued; seek shelter instead. Once sheltered, take off wet clothes and replace with dry if available. Refuel your body with food and water. Do NOT consume alcohol, caffeine or tobacco. Build a fire. Get inside a sleeping bag if available. If you're not alone, huddle with others to share body heat.

For more details see also the Outdoor Action Guide.