What should you do first if you're caught out in the cold? Stop moving and stay put, get out of the wind, and put on extra layers as soon as you start to feel cold. Then watch yourself and everyone with you for the early signs of hypothermia and frostbite, keep any shelter small and ventilated, melt snow before you drink it, and make yourself easy to find. This guide takes those steps in order, using guidance from the CDC, the National Weather Service, the National Park Service, the USDA Forest Service and the U.S. Army survival manual.
This article is general safety information, not medical advice. In an emergency, call 911.
Why Cold Changes the Rules
The Army's survival manual puts it plainly: cold "decreases your ability to think and weakens your will to do anything except to get warm" (U.S. Army FM 21-76, Chapter 15). The same manual notes that in a cold environment you need fire to get warm and shelter from the cold, wind, rain or snow, and that if anyone is injured, first aid comes first no matter the climate.
It also doesn't take a blizzard. The CDC notes that hypothermia can happen even at cool temperatures above 40°F if a person gets chilled from rain, sweat or cold water (CDC: Preventing Hypothermia).
Step 1: Stop, Stay Calm, Stay Put
The USDA Forest Service's advice is short: as soon as you realize you may be lost, stop, stay calm, stay put. It also says that if it's nightfall, or you're injured or near exhaustion, stay in place (USDA Forest Service: If You Get Lost).
The National Park Service agrees: changing location makes it harder for authorities to find you, so move only if there is an immediate threat to life (NPS: Outdoor Emergency Plan).
Step 2: Get Out of the Wind and Layer Up Early
The National Weather Service advises anyone outdoors in extreme cold to dress in layers, cover exposed skin, and seek shelter from the wind as much as possible (NWS: During Extremely Cold Weather). The NPS adds a timing rule: if you begin to feel cold, put on any extra layers you have with you and button or zip them all up.
How you wear those layers matters. The Army's memory aid is COLD:
- C, keep clothing clean. Clothes matted with dirt and grease lose much of their insulation.
- O, avoid overheating. Sweat dampens clothing, which insulates less, and evaporating sweat cools you. Open your jacket or drop a layer before you start sweating.
- L, wear clothes loose and in layers. Several light layers trap dead air between them, which insulates better than one equally thick layer. Tight clothing and footwear restrict circulation and invite cold injury.
- D, keep clothing dry. Brush off snow and frost before you go into a heated shelter. Dry damp socks or mittens near your body.
Also skip cotton, because it won't keep you warm when it's wet, and wear a windproof, hooded outer layer over insulating wool or synthetic garments (NPS: Yellowstone Winter Safety). The NWS adds: wear a warm hat, choose mittens over gloves, and if you get wet, change into dry clothing immediately.
Step 3: Know the Signs of Hypothermia
Hypothermia is hard to spot in yourself. Because it affects the brain, the CDC warns, a person may not know it is happening. That makes checking on each other part of the plan.
| Who | Warning signs (CDC) |
| Adults | Shivering, exhaustion or feeling very tired, confusion, fumbling hands, memory loss, slurred speech, drowsiness |
| Infants | Bright red, cold skin and very low energy |
The CDC lists people who remain outdoors for long periods, such as hikers and hunters, among those at higher risk, along with older adults without enough food, clothing or heating, babies sleeping in cold bedrooms, and people who drink alcohol or use illicit drugs.
A body temperature below 95°F is an emergency. Get medical attention immediately. Until help arrives, the CDC says to:
- Get the person into a warm room or shelter, and remove any wet clothing.
- Warm the center of the body first (chest, neck, head and groin), using skin-to-skin contact under loose, dry layers of blankets or clothing if that's what you have.
- Give warm drinks only if the person is conscious, and never alcohol.
A person with severe hypothermia may be unconscious and may not seem to have a pulse or to be breathing. Handle them gently, get emergency help immediately, and perform CPR even if the person appears dead, while you keep warming them.
For more on preventing it, see our hypothermia prevention and treatment guide.
Step 4: Catch Frostbite Early
The NWS warns that frostbite can happen in minutes, especially on fingers, toes, nose and ears. According to the CDC, redness or pain in any skin area may be the first sign. Other signs are a white or grayish-yellow skin area, skin that feels unusually firm or waxy, and numbness (CDC: Preventing Frostbite).
If you see it, check for hypothermia too, then:
- Do: get to a warm room as soon as possible, remove wet clothing, and warm the area in warm, not hot, water. If there's no warm water, use body heat; an armpit can warm frostbitten fingers.
- Don't: rub the area with snow or massage it at all. Don't use a heating pad, heat lamp, stove, fireplace or radiator; numb skin can burn easily. Unless absolutely necessary, don't walk on frostbitten feet or toes.
The CDC's advice is to seek medical care if you notice signs of frostbite, because frostbite should be checked by a health care provider.
Step 5: Keep Your Shelter Small, Insulated and Vented
Whatever you're sleeping in, these Army cold-weather rules apply (FM 21-76):
- Stay off low ground. Ravines, narrow valleys and creek beds collect heavy cold air at night and are colder than the surrounding high ground. The NWS calls this "cold air drainage": overnight, a valley fills from the bottom with cold layers of air (NWS: Mountain/Valley Fog).
- Keep it small. A shelter larger than you need steals body heat rather than saving it.
- Block the entrance with a pack or snow to keep heat in and wind out.
- Never sleep directly on the ground. Lay down pine boughs, grass or other insulating material so the ground doesn't absorb your body heat.
- Ventilate. Any open flame can make carbon monoxide, which is colorless and odorless. Never fall asleep without turning out your stove or lamp, and never burn a fire in a shelter without ventilation.
Step 6: Melt Snow Before You Drink It
Bundled in layers, you may not notice you're losing body moisture. The Army manual says your need for water is as great in a cold environment as in a warm one. Melt snow and ice completely before you put them in your mouth, because melting them in your mouth takes away body heat. If you have a choice, melt ice: a cup of ice yields more water than a cup of snow and melts faster. Once you have water, keep it next to you so it doesn't refreeze.
Step 7: Make Yourself Easy to Find
The NPS recommends blowing a whistle often, which saves the energy you'd spend yelling, and laying out your shelter material or rocks in a shape that can be seen by planes or helicopters. The best signal of all is the one you send before you leave: a trip plan with someone at home who knows when to expect you back. Our guide on using a signal mirror covers another daytime signal.
Frequently Asked Questions
Can you get hypothermia when it isn't freezing?
Yes. The CDC says hypothermia can occur at cool temperatures above 40°F if a person becomes chilled from rain, sweat or submersion in cold water.
Should you rub frostbite to warm it up?
No. The CDC says not to rub the frostbitten area with snow or massage it at all. Warm it in warm, not hot, water or with body heat, and have it checked by a health care provider.
Why does the Army say to avoid overheating in the cold?
Sweat dampens your clothing, which lowers its insulation, and evaporating sweat cools your body. Open a jacket or drop a layer before you start to sweat.
Build Your Cold-Weather Kit
Extra layers, a hat and mittens, a shelter or emergency blanket, a way to make fire, a whistle and a first aid kit cover most of the steps above. Browse our apparel and accessories, shelter and tents, camping and survival gear and first aid kits, and read Pillar 1: Shelter for the bigger picture.
