The first shelter question is not "what can I build?" It is what is killing me fastest? Wind, wet, cold ground, or heat. Fix that first.
The decision tree
Cold and wet
- Get out of the wind.
- Get off the ground.
- Get dry.
- Add insulation.
- Only then build something bigger.
A tarp, a debris pile, or a vehicle can be enough. A large shelter is hard to heat.
Snow
A snow cave or trench can be warm, but only if you know the slope is safe and you keep a ventilation hole open. Do not build one if you lack avalanche training. Mark the entrance so rescuers can find it.
Hot and exposed
Shade is the shelter. Use a tarp or natural shade, travel at night, and avoid midday exertion. A shelter that traps heat is worse than no shelter.
Vehicle
Stay with the vehicle unless it is unsafe. It is easier to find and provides shelter. Run the engine only briefly for heat, and keep a window cracked. Do not run the engine in a closed garage or with a snow-blocked tailpipe.
Urban
Close windows and doors. Move to an interior room above ground during a chemical release. Seal gaps with tape or towels only if officials tell you to. Listen to official instructions.
Site selection
Look for a dry, level spot away from dead trees, flash-flood paths, and rockfall. Stay near water and fuel, but not in a drainage. Do not camp under a single dead tree or in a dry wash.
Insulation and ventilation
- Put a foam pad, branches, leaves, or cardboard under you.
- Change out of wet clothing.
- Keep the shelter small.
- Keep a high vent and a low vent open if there is any flame.
- Never sleep with a smoldering fire in a sealed space.
What not to do
- Do not build under a dead tree.
- Do not camp in a dry wash or flood path.
- Do not use a fuel-burning stove in a tent without manufacturer approval.
- Do not ignore shivering, confusion, or slurred speech.
The short version
Stop the heat loss first: wind, ground, wet. Then improve the shelter. Ventilation is part of the shelter whenever there is fire.
For the field version, see Stop heat loss, Choose a shelter site, and Ventilate any shelter with a flame in Fieldry.
Sources
- CDC — Hypothermia: https://www.cdc.gov/environmental-health/weather-related-illness/about/hypothermia.html
- Ready.gov — Shelter: https://www.ready.gov/shelter
- Ready.gov — Car Safety: https://www.ready.gov/car