Guide · First steps

The rule of threes

When everything feels urgent, the rule of threes helps you decide what to deal with first. It's a rough guide to how long a person can last without each basic need.

The rule

• 3 minutes without air.
• 3 hours without shelter in harsh conditions — cold, wet, wind or fierce heat.
• 3 days without water.
• 3 weeks without food.

These numbers are not exact. A fit adult in mild weather may last much longer; a child, an older person or someone injured may last far less. Heat, cold, effort and illness all shorten the times. Treat them as an order of priority, not a countdown.

What it means in practice

1. Air and immediate danger first. Get away from smoke, fumes, rising water or anything that could fall. Make sure everyone is breathing. Deal with heavy bleeding straight away — that sits alongside air at the top of the list.
2. Shelter next. Most people who die outdoors die from the cold, not from hunger or thirst. Get out of the wind and rain, get off the cold ground, and add layers before you start to shiver hard.
3. Then water. Find a source and a way to make it safe. Start drinking little and often. Don't wait until you're desperate.
4. Food last. You can go a long time without eating. It will feel unpleasant, but it is rarely what puts you in danger. Don't burn energy or take risks hunting for food while shelter and water are still unsolved.

Where fire and signalling fit

Fire supports several needs at once: warmth, drying clothes, boiling water and being seen. Signalling for help can shorten the whole ordeal, so do it early — a whistle, a bright jacket laid out or a phone call to your local emergency number (112 in Europe and many other countries, 911 in North America) costs very little.

Common mistakes

• Spending the first hours looking for food while getting cold and wet.
• Drinking untreated water because you're thirsty, then getting ill.
• Walking off in a panic instead of making shelter while it's still light.

Keep coming back to the list. When something changes — the weather turns, someone gets hurt — run through it again from the top.

This article is in the Grid Survivor app, searchable with no signal. Get the app · £4.99