Emergency bivy and space blanket

The light shelter that lives in the day pack for the night you did not plan, and how to get the most warmth out of it.

What you need

Stop early. Pick your spot while there is still light.
Get out of the wind: behind a rock, in thick trees, in a hollow that is not wet.
Get off the ground. Sit on the pack, a pad or a thick pile of boughs. The cold ground takes more heat than the air.
Put on every layer you have, then the toque and dry socks.
Get into the bivy bag or pull the survival bag over you, feet first, with your face out of it so you do not soak it with your breath.
If you have a space blanket, wrap it close around you under the bag or rig it as a small roof that reflects a fire's heat back onto you.
Eat something and drink something before you settle in.
Move your fingers and toes, tense and relax your muscles, and change position when you get cold.

Don't

Do not zip or close the bag over your face. Condensation soaks you and you need air.
Do not trust a space blanket alone on cold ground or in wind. It tears and blows off.
Do not keep walking in the dark to avoid the night out. That is how people get hurt.

Danger

You will get wet inside from your own sweat and breath. Open it up when you start to feel damp.
Shivering that stops while you are still cold is a bad sign. See Hypothermia.
Old space blankets split along the folds. Replace one that has been in the pack for years.

A night out in a bag is long and uncomfortable, and you will be fine. That is the whole point of carrying it.

If you have a tarp as well, pitch it low over you. See Tarp lean to.

Updated 2026-09-22