How to Survive in Cold Weather in the Wilderness

To survive in cold weather in the wilderness, stop heat loss before you try to make heat. Stay dry (manage sweat as carefully as snow), get out of the wind, put insulation between you and the ground, add layers before you start shivering, and keep eating and drinking so your body has fuel to burn. Watch yourself for the early signs of hypothermia, and if conditions turn, shelter early rather than pushing on.

How your body loses heat in the cold

Every survival decision makes more sense once you know where your heat goes. You lose it in five main ways:

• Conduction: direct contact with something cold. Sitting or lying on snow or frozen ground drains heat fast.
• Convection: moving air or water carrying heat away. Wind is the big one, and it is why the same temperature feels far worse on an exposed ridge.
• Evaporation: sweat and wet clothing pull heat from your skin. Damp layers lose much of their insulating value.
• Radiation: heat leaving any exposed skin, especially your head and neck.
• Respiration: every breath of cold, dry air has to be warmed and moistened.

Your body is a furnace with a limited fuel supply. Insulation, shelter and food all work by slowing one of these losses or topping up the fuel.

How to survive in the cold: what to do, in order

1. Stay dry. Shed a layer before you start sweating on a climb, not after. Brush snow off before it melts into your clothes. Avoid cotton, which holds water and stays cold. Wool and synthetics keep more of their warmth when damp.
2. Get out of the wind. Drop below a ridgeline, move into trees, or put a boulder, snowbank or your pack between you and the wind. Even a small windbreak makes a big difference.
3. Insulate from the ground. A foam pad, your pack, spruce boughs, a pile of dry leaves or even a rope coil under you stops conduction. Never sit directly on snow.
4. Layer early. Put your insulated jacket on the moment you stop moving, before you feel cold. It is much easier to stay warm than to rewarm.
5. Build or improve shelter. If you carry a tent or bivy, pitch it in a spot out of the wind and away from avalanche slopes and dead trees. Without one, a tarp, a debris shelter or a snow trench can be enough to get through a night. Keep it small, because a small space holds heat better.
6. Make fire if you can do it safely. Fire dries gear and lifts morale, but it costs energy and time. In deep cold, a well insulated shelter is often more valuable than a struggling fire.
7. Eat and drink steadily. Cold makes your body burn more energy. Snack on calorie-dense foods (nuts, cheese, chocolate, nut butter) every hour or so, and keep drinking even when you don't feel thirsty. Warm drinks help both warmth and morale. Eat something fatty before sleeping.
8. Signal and stay put if you are lost or hurt. If someone knows your plan, searchers will start where you were meant to be. Use a whistle (three blasts), a bright jacket, or a satellite messenger or personal locator beacon if you carry one.

Recognizing hypothermia and frostbite early

Hypothermia rarely announces itself. The cold steals your judgment before it steals your strength, so you need to watch for small signs, in yourself and in anyone with you.

Early warning signs (act now):

• Shivering you can't stop
• Clumsy hands, fumbling zippers or straps
• Stumbling, slurred speech, short temper ("the umbles": stumbles, mumbles, fumbles, grumbles)
• Feeling unusually tired or wanting to just sit down

What to do: stop, get out of the wind, replace any wet layers with dry ones, add insulation (including a hat and something under you), eat sugary and fatty food, and drink something warm if you can. Get into a sleeping bag if you have one.

Emergency signs: shivering that stops while the person is still cold, confusion, extreme drowsiness, or loss of consciousness. This is a medical emergency. Handle the person gently, insulate them, and call for rescue immediately.

Frostbite usually starts in fingers, toes, nose, ears and cheeks. Look for skin that goes numb, white, grey or waxy. Warm mildly affected areas against your own body (hands in armpits, for example). Don't rub frozen skin, and don't thaw it if there's a chance it will freeze again before you reach help. Get medical care for anything beyond mild frostnip.

How to read the weather before it turns

Most cold-weather emergencies begin with a change in the weather that nobody acted on. You don't need to be a meteorologist to see the signs.

• Clouds that thicken and lower over several hours, especially high, wispy clouds turning into a grey sheet, often mean a front and snow are coming.
• Lens-shaped clouds over mountains signal strong winds higher up.
• Falling barometric pressure on a watch or altimeter points to worsening weather. A fast drop means change is coming quickly.
• Cold air pools in valleys and hollows on clear, calm nights, so low camps can be much colder than nearby slopes.

Check an official forecast and any avalanche bulletin before you go, and tell someone your route and your turnaround time.

A worked example

Sam is on a solo overnight snowshoe trip. At 1 p.m. she notices the high, thin clouds from the morning have thickened into a low grey layer, and her watch shows the pressure dropping. She is two hours from the car.

She turns back instead of pushing to her planned camp. At 3 p.m. the snow starts and the wind picks up across an open meadow, so she stops at the tree line, puts on her puffy jacket before she feels cold, and eats a handful of nuts and chocolate.

By 4 p.m. her fingers are clumsy on her pole straps. She recognizes it, swaps her damp liner gloves for the dry pair in her pack, and drinks warm tea from her flask. She reaches the car at 5:30 p.m., tired but fine. Each step she took was small. The decision that mattered most was turning around at the first sign.

Common cold-weather mistakes

• Sweating on the way up. Start a climb slightly cold and vent early.
• Waiting to feel cold before layering. By then you are already losing ground.
• Skipping food and water because stopping is uncomfortable. Eat little and often.
• Sitting on snow for breaks. Always put something under you.
• Ignoring the turnaround time because the summit or camp feels close.
• Going without a plan on file. Leave your route and expected return with someone reliable.

Common questions

How do you survive winter in the wilderness overnight?

Pick a sheltered spot out of the wind and away from low hollows, insulate well underneath you, and sleep in dry layers. Eat a fatty snack before bed, keep a bottle of warm water in your sleeping bag, and wear a hat. Keep tomorrow's gloves and boot liners inside your bag so they don't freeze.

How long can you survive in extreme cold?

It depends on temperature, wind, wetness, clothing, shelter and your own health, so there's no single number. A dry, well-dressed person in shelter can last a long time, while someone wet in the wind can get into trouble within hours. That is why staying dry and out of the wind comes first.

What is the most important thing for surviving the cold?

Stopping heat loss: staying dry, blocking wind and insulating from the ground. Fire and food help, but they can't keep up with a wet person sitting on snow in the wind.

Should you keep moving to stay warm?

Moving makes heat, but it also burns energy and can make you sweat. Light movement, like swinging your arms or walking in place, helps when you're chilled. If you are lost, tired or the weather is bad, sheltering in place is usually safer than pushing on.