Frostbite

2 min read

Frostbite is the freezing of skin and tissue. It mostly affects fingers and toes, nose, ears, cheeks, and chin.

First signs (CDC): redness or pain in an area of skin.
Then: white or grayish-yellow skin that feels unusually firm or waxy, and numbness. The victim often feels nothing, which is why it is discovered late. Check your partner's face regularly.
Frostnip: pale, numb skin that recovers completely when warmed. It is the warning: warm the area (hands in armpits, cover the face) and protect yourself better.

What to do

Treat hypothermia first if present; it takes priority.
Decide whether you can thaw. If there is a risk the area will refreeze (for example, you have to keep walking in the snow), it is safer to leave it frozen until you reach a place where it will stay warm. Freezing, thawing, and refreezing causes much more damage.
Remove rings, watches, and tight clothing from the affected area.
Do not walk on frostbitten feet unless it is essential.
If you can keep it warm, thaw in warm water: 98.6 to 102.2 °F (37 to 39 °C). Without a thermometer, it should feel warm to the touch; test with a healthy hand for 30 seconds. It usually takes about 30 minutes; the area turns red or purple, soft, and it hurts. If there is no water, use body heat (armpits, another person's abdomen).
Dry without rubbing: let it air-dry or pat gently.
Protect the area: dry gauze between the fingers or toes, do not pop blisters, and seek medical attention. For pain, an over-the-counter pain reliever according to the label.

Trench foot

FM 21-76 warns about trench foot (immersion foot): damage from keeping your feet wet for a long time at temperatures just above freezing. It does not need ice. Prevention is keeping your feet dry: change socks daily or as soon as they get wet, and carry spare socks in a waterproof bag. Dry and warm your feet every night.