When a person's body drops 2 degrees below 98.6 ºF or 37ºC, their organs have difficulty functioning. If their body continues to cool, they will lose consciousness at about 86ºF/30ºC and at 77ºF/ 25ºC their heart will stop. This reduction in body temperature is called hypothermia.

Body heat is lost in a variety of ways:

1. Radiation-heat from the body is released to warm up the air around it
2. Breathing-heat is lost by warming up the air taken in with each breath and exhaling it
3. Conduction-heat is moves from a warmer place to a cooler place (eg. from the body to the cold ground)
4. Evaporation-water on the skin is turned in vapor by body heat, cooling the skin
5. Convection-air near the skin is warmed and rises, cool air fills the space left behind

Mild hypothermia
Casualty is conscious, shivering and logical.
They should be taken to warm shelter, given dry clothing and warm liquids (NOT COFFEE)

Moderate hypothermia
Casualty is illogical, clumsy, and sleepy and stops shivering.
Treat the casualty as above but do not give any liquids until they have regained motor control.

Severe hypothermia
Casualty is unconscious, has a slow or absent pulse and pale or bluish colored skin.
It is important that they receive medical help as soon as possible. If there is no pulse, begin CPR only if it can be continued until medical help arrives.

Handle moderate and severe hypothermia casualties carefully, disturbances may cause the casualty's heart to stop

Don't assume the person is dead until they are "warm and dead" (Wilderness Guide)

Frostbite is the "freezing of body tissues with the formation of ice crystals" (Wilderness Guide, pg. 112) There are two types of frostbite:

Surface Frostbite-just the top layer of skin is affected and usually doesn't cause permanents damage. If left untreated it can progress to deep frostbite.

Deep Frostbite- this is when both the skin and the tissue below it is frozen. It's more serious than surface frostbite and may cause deformities or require amputations.

Signs

Skin appears white and waxy or if severe blue/purplish
pain or numbness
hard to the touch

Procedure

small affected areas (eg. fingers/toes) can be rewarmed by placing them in direct contact with warm skin
deep frostbite should receive medical attention
the frozen part should not be used

If medical help is not available, then the frozen area should be placed in a tub of warm water until the part is pink,then dry the area and treat any wounds.

Remember:
the rewarmed area is extra-sensitive to the cold
don't apply direct heat (eg. heating pad)
don't break any blisters