Key takeaways
- Frostbite is the freezing of skin and tissue, usually on fingers, toes, ears, nose, and cheeks.
- It progresses: frostnip (reversible) → superficial → deep frostbite (risk of permanent damage).
- Early signs are numbness and pale, waxy, hard skin; rewarmed tissue is intensely painful.
- Don't rewarm if refreezing is possible, and never rub frozen tissue — get to definitive care.
This is general educational information, not medical advice. Seek professional medical care for frostbite, and treat life-threatening hypothermia first.
What frostbite is
Frostbite occurs when skin and the tissue beneath it actually freeze, forming ice crystals that damage cells and cut off blood flow. It targets the extremities — fingers, toes, ears, nose, cheeks — and is driven by cold, wind, wet, and anything that reduces circulation, such as tight boots or dehydration.
Stages and signs
- Frostnip — cold, numbness, pale or red skin; reversible with warming, no lasting damage.
- Superficial frostbite — skin turns white or waxy and feels firm; clear blisters may appear on rewarming.
- Deep frostbite — skin is hard, white or blotchy, and numb; risks permanent tissue loss.
A climber notices a partner’s nose has gone white and waxy. With shelter and no risk of refreezing, they rewarm it gently against warm skin, avoid rubbing it, cover it, and plan to descend for medical evaluation.
Field response
Protect the area, and only rewarm when you can keep it warm — refreezing causes far worse damage than staying frozen briefly. Never rub frozen tissue. Manage hypothermia first if present (see hypothermia vs frostbite), and prevent frostbite through layering, dry hands and feet, and staying fueled and hydrated.
The bottom line
Frostbite is the freezing of local tissue and can cause permanent damage if it advances, so catching the early numb, pale, waxy stage and getting warm matters. In the field, the cardinal rules are don't refreeze and don't rub — and remember that hypothermia, the whole-body emergency, takes priority when both are present.
Frequently asked questions
What are the early signs of frostbite?
The earliest stage, frostnip, causes cold, numbness, tingling, and pale or red skin and is fully reversible. As it progresses to true frostbite, skin turns white or grayish, feels waxy, and goes hard or numb. On rewarming, frostbitten tissue is intensely painful and may blister.
How do you treat frostbite in the field?
Get out of the cold and protect the area. Critically, do NOT rewarm a frozen part if there is any chance it could refreeze before reaching care, and never rub or massage it. When safe to rewarm, use warm (not hot) water around 37–39°C, keep the area protected, and evacuate for medical treatment.
What's the difference between frostbite and hypothermia?
Frostbite is a localized injury where specific tissue freezes, while hypothermia is a drop in your whole-body core temperature. They share the same cold causes and often occur together — but hypothermia is the more immediately life-threatening, so it's treated first. See our hypothermia vs frostbite comparison.
Sources
- Frostbite & cold injury — Wilderness Medical Society
- Cold weather & frostbite — CDC
- Cold injury prevention — National Park Service