Hypothermia and Frostbite

Hypothermia

Hypothermia is a dangerously low body temperature. It sneaks up, because one of its early effects is poor judgment. CDC’s warning signs in adults ¹:

• shivering, exhaustion or feeling very tired
• confusion, memory loss, slurred speech
• fumbling hands
• drowsiness

If you can take a temperature and it’s below 95 °F, get medical attention immediately ¹.

What to do ¹:

1. Get the person into a warm shelter or at least out of the wind.
2. Remove wet clothing.
3. Warm the center of the body first: chest, neck, head, and groin, with blankets, dry layers, or skin-to-skin contact in a sleeping bag.
4. Give warm, non-alcoholic drinks only if they’re conscious.
5. Keep them warm and wrapped, including the head and neck, and get care.
6. If they’re unresponsive with no pulse, start CPR and keep warming.

Handle a severely hypothermic person gently and keep them lying down; don’t have them walk or exercise to warm up.

Frostbite

Frostbite is frozen tissue, most often the nose, ears, cheeks, chin, fingers, and toes. Because the area goes numb, people often don’t notice it ². Signs ²:

• redness or pain, often the first sign
• skin that turns white or grayish-yellow
• skin that feels unusually firm or waxy
• numbness

What to do ²:

• Get medical care, and move to a warm place; remove wet clothing.
• Rewarm in warm, not hot, water, or with body heat (fingers in an armpit, a warm hand over a cheek).
• Don’t walk on frostbitten feet or toes unless you must.
• Don’t rub or massage the area.
• Never use a heating pad, heat lamp, stove, fireplace, or radiator: numb skin burns easily.

In the field, don’t rewarm a frozen foot if it might refreeze before you reach help; thawing and refreezing does more damage. If someone has both, treat hypothermia first and get emergency care ².

Prevention

• Dress to stay dry and cover exposed skin: hat, face covering, mittens (see Dressing for Cold) ¹.
• Watch the wind chill: at -19 °F, exposed skin can freeze in 30 minutes ³.
• Buddy checks: look at each other’s faces for white patches every so often; you can’t see your own.
• Eat, drink, and rest: fatigue, dehydration, and hunger set people up for hypothermia. Alcohol makes you feel warm while you lose heat faster.
• Change out of wet clothes promptly, and don’t let a sweaty base layer cool on you at a stop.
• Turn around early: numb fingers that won’t warm up, a stumbling partner, or rising wind are reasons to end the day.

Cold water is different

Water pulls heat from the body far faster than air at the same temperature. Falling through ice or capsizing in spring meltwater starts with cold shock, which can drown you in the first minutes, followed by progressive loss of strength in arms and legs; hypothermia comes later ⁴. Keep your head up, get out or get your body out of the water as much as possible, and in a canoe on cold water, dress for immersion (see Ice Safety and Ice Thickness).

Try it

Practice a hypothermia wrap with a partner and your winter gear: a ground pad, sleeping bag, dry layers, a hat, and a hot water bottle at the chest, wrapped in a tarp. Time how long it takes to set up, in mittens.

What to take from this

Hypothermia shows as shivering, exhaustion, confusion, fumbling, slurred speech, and drowsiness; below 95 °F needs medical care. Shelter the person, remove wet clothes, warm the core first, and give warm drinks only if alert. Frostbite shows as red or painful, then white or waxy, numb skin; rewarm in warm, not hot, water or with body heat, never rub it or use a stove, and don’t thaw it if it may refreeze. Prevent both by staying dry, covering skin, watching wind chill, eating and drinking, and turning back early.