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Tsunami: what to do

A tsunami is a series of huge ocean waves, usually caused by an earthquake under the sea. This page helps you recognize the natural warnings and get to safety quickly.

Do this now

  1. If you feel strong shaking, or shaking that lasts a long time, drop, cover, and hold on until it stops. Then move at once.
  2. Go to high ground or as far inland as you can. Do not wait for an official warning.
  3. Leave on foot if you can. Roads can jam, and cars may be caught in the waves.
  4. Go up, not toward the water. Never go to the shore to watch.
  5. Stay away from the coast until officials say it is safe, even after the first wave.

Natural warning signs

Your own senses may be the first and only warning, especially if the earthquake was close.

  • Strong shaking, or shaking that lasts a long time
  • The sea suddenly pulling back and showing the sea floor
  • A loud roar from the ocean, sometimes like a train or a jet

If you see or feel any of these on the coast, go to high ground immediately. Do not wait for a siren, a text, or confirmation. Sudden drawing back of the water is a reason to run, not to look.

Official warnings

Tsunami warning centers watch earthquakes and ocean sensors, and local officials pass on alerts by sirens, phone alerts, radio, and television. In the United States, the National Tsunami Warning Center issues alerts. Other countries have their own agencies.

Warnings can arrive minutes after a nearby earthquake, which may be too late. Natural signs matter most when the source is close. A distant earthquake can give hours of notice, so use that time to leave calmly and follow official instructions.

Where to go

Know your evacuation routes before you need them. Look for blue tsunami evacuation signs in coastal areas, and ask local officials about your area.

Aim for high ground, or as far inland as you can get. US guidance suggests at least 30 meters (100 feet) above sea level or 1.5 kilometers (1 mile) inland, where that is possible. If you cannot reach high ground, a strong, tall building and its upper floors may be your only choice. Follow local guidance, because the right answer depends on where you are.

... warning "Waves can be tens of meters high" Tsunami waves can range from about 3 to 30 meters (10 to 100 feet) and move quickly onto land. Even a smaller tsunami can carry strong currents, debris, and boats.

There will be more than one wave

A tsunami is a series of waves, and the first is often not the largest. They can keep arriving for hours.

Stay away from the coast, harbors, and low ground until officials say it is safe. Do not go back to see the damage or collect belongings after one wave. The sea may look calm between waves, and that is when people are caught.

On a boat or in the water

  • If you are on a boat in deep water when a warning is issued, officials often advise heading out to sea. If you are in a harbor, go inland.
  • If you are caught in the water, grab something that floats, such as a log or a raft.

Follow your local harbor and maritime authority for guidance.

Stay safe afterward

Wait for the official all clear before going back. Water and debris can leave unsafe buildings, broken gas lines, and live wires. Use text messages instead of calls to reach family so networks stay open for emergencies.

... tip "Make a plan" If you live on or visit a coast, agree on a meeting place on high ground, and practice the walking route with your family.