What to do in the first 15 minutes

Outside the immediate destruction area, what decides who comes through a nuclear detonation is not luck: it is the following fifteen minutes. There is a real margin between the explosion and fallout coming down, and that margin gets used for one thing — reaching a better place — or it gets wasted.

Minute 0: the flash

1. Do not look. Turn your eyes away immediately. The flash can cause temporary blindness at long distances.
2. On the ground, face down. Face towards the floor, hands under your body, behind anything solid: a kerb, a low wall, a ditch, a heavy vehicle.
3. Mouth slightly open. It equalises pressure and reduces eardrum damage.
4. Stay down until the wave has passed and debris stops falling. There can be more than one pressure front.

Minutes 1 to 15: get to the best available place

Once the wave has passed, get up and use the margin. The priority is not to get further away: it is to get into a better building.

1. Look for masonry: brick or concrete. A large building, a basement, an underground car park, a metro station.
2. Go down, or towards the centre. Away from the roof, away from external walls and away from the street.
3. If you are already in such a building, do not leave. Staying in a mediocre place beats crossing the street for an excellent one if it takes too long.
4. Leave belongings behind. The only luggage worth having is a bag that was already packed.
5. Do not go looking for anyone. Each person shelters where they are; reunification comes later and the family plan handles it.

Where you are	What to do
In the street	Nearest masonry building, towards the basement or centre
In the car	Stop, get out and find a building; the car does not protect
In a wooden or prefab house	Move to a masonry building if one is close
In a basement or the metro	Stay: you are already in the best place
In an attic or top floor	Go down to middle floors or the basement

On the way in: fast decontamination

If you were out in the open after the explosion, you are carrying radioactive dust. Before settling in:

1. Take off your outer clothing and put it in a sealed bag, far away.
2. Wash what was exposed: face, hands, neck. With soap and water if there is any; with a wipe or damp cloth if not.
3. Blow your nose and wipe your eyelids with a clean cloth.
4. If there is a shower, use it: warm water, soap, no hard scrubbing and no conditioner.

The full detail is in radiological decontamination.

And then: stay put

From minute fifteen onwards, the job is not going out. The general rule is 24 hours inside, unless officially instructed otherwise, because fallout radioactivity decays very quickly in the first hours.

• Turn on the radio and check it at intervals.
• Send a text to the family plan contact: “I’m fine, I’m at X.” One message, not calls.
• Eat and drink only what was sealed.
• Do not burn anything in a closed space.

Exactly where to position yourself inside the building, and why 24 hours is that number, is in where to shelter from fallout.