5.1 — How to Read a Warning, and the Shape of Every Disaster Response

Almost every natural disaster gives warning.

Cyclones give days. Floods give hours to days. Volcanoes give days to weeks. Tsunamis give minutes to hours. Heatwaves give days.

Earthquakes give seconds, and even those are increasingly detectable in the moments before the shaking arrives.

**Which means the dominant cause of harm is not the absence of warning. It is what people do with it.

Why people do not act on warnings

Five reasons, all documented, and all correctable by knowing them.

Normalcy bias (1.1). The previous three warnings came to nothing.

Waiting for confirmation. **People do not evacuate on a warning. They evacuate when they see a neighbour evacuating, or when somebody they trust tells them to. This is why the first mover matters so much.

Underestimating the specific hazard. Particularly water: almost nobody has an accurate intuition for how much force moving water carries (5.4).

Not wanting to leave possessions or animals. A very large proportion of people who die in floods and fires died going back or refusing to leave for this reason.

And the cost of a false alarm feels concrete while the benefit of evacuating feels hypothetical. Leaving costs money, time and inconvenience today; the flood might not come.

The correction to all five is the same: decide the trigger in advance, in writing, before the situation.

The trigger rule

The single most useful idea in Part 5.

Decide now, calmly, what condition will make you act — and then act on it without re-deciding.

Examples of a good trigger.

If an official evacuation order is issued, we go, immediately, regardless of how it looks outside.

If water reaches the bottom of the front step, we move upstairs with the kit.

If the river gauge reaches this level, we leave.

If we feel shaking near the coast, we go inland and uphill without waiting for a warning (5.3).

The reason this works: in the moment you will look outside, see that it is not that bad yet, and defer.

**Everybody does. A pre-set trigger removes the decision from the compromised version of you.

The universal sequence

Every disaster response in Part 5 has the same five steps, in the same order.

1. Know your hazard

Ten minutes, once.

**What actually happens where you live? Earthquake zone? Flood plain? Cyclone coast? Landslide slope? Wildfire interface?

**Local authorities publish hazard maps in most places. Look at yours.

**And ask a neighbour who has been there thirty years. They know where the water came to in the bad year, and that is frequently better information than any map.

2. Have the trigger and the plan

Where you go. Which route. Who takes whom. Where you meet if separated. Who the out-of-area contact is (1.4).

And critically: two routes, because the obvious one is frequently the one that is blocked or jammed.

3. Have the kit ready

9.2 covers it fully.

The principle: a bag that is already packed, by the door, that you can pick up and leave with.

A kit that has to be assembled during the emergency is not a kit.

4. Act on the trigger

Early rather than late.

Evacuating early is calm, has road capacity, and is reversible. Evacuating late is a traffic jam in the dark, and the roads out of a disaster area become impassable exactly when everybody decides at once.

5. Stay informed, from one reliable source

Official emergency services, the meteorological department, and local authority channels.

Not social media, where the ratio of rumour to information during a disaster is very poor and where old photographs from previous events circulate constantly as current.

And have a way to receive information without power or mobile data: a battery or wind-up radio is genuinely worth having in a cyclone or flood area.

The warning vocabulary

Terms are used inconsistently between countries and the underlying distinction is standard.

**A watch, or an alert, means: conditions are favourable for this to happen. **Prepare. Check the kit, fuel the vehicle, review the plan.

**A warning means: it is happening or is imminent. Act on the trigger now.

And colour-coded systems generally escalate green, yellow, orange, red — with orange meaning be prepared to act and red meaning act.

Learn what your local system uses, once.

Evacuation, done properly

Because it is the most common action in this Part and it is done badly.

Go early.

Take: documents, medication, money, phone and charger, water, the kit, and any dependent's essentials.

Turn off gas and electricity at the mains if advised, and water if flooding is expected.

Lock the house and tell somebody where you are going.

Take pets. Refusal to leave animals is a documented cause of death, and most systems have improved provision for this — check in advance rather than in the moment.

And use the designated route. Locals frequently take a shortcut that is exactly the road that floods, and this recurs in incident reviews.

Do not go back. The decision made in advance (1.3).

Sheltering in place

When it is the right answer — some earthquakes, some storms, chemical incidents, and cases where evacuation routes are already unsafe.

Interior room, away from windows.

Lowest floor for wind; upper floor for water. These are opposite and getting them the wrong way round is a fatal error, so the rule is worth memorising: wind goes down, water goes up.

Have the kit, the radio and a way to signal.

And tell somebody outside the area that you are sheltering rather than evacuating, so that anybody looking for you knows.

After

Three things, because the aftermath causes a significant share of injuries.

Do not return until told it is safe. Structural damage, live wires, gas, and contaminated water are all invisible.

Assume standing water is contaminated and electrically live.

And expect the second event. Aftershocks. A second surge. A returning fire front. The second half of a cyclone after the calm eye passes (5.5). A large number of casualties occur in the period when people believe it is over.

What to do with this page

Decide your trigger now, in writing. It is the highest-value item in this Part.

Learn your actual hazard and ask a neighbour who has been there thirty years.

Two evacuation routes, not one.

Wind goes down, water goes up.

And expect the second event. The period when everybody thinks it is over is when a large share of the casualties happen.

Next: 5.2 — earthquake, where you have seconds and the correct action is counter-intuitive.