Tsunamis

A tsunami is a series of powerful waves, usually caused by an undersea earthquake, landslide or volcano. It can reach shore within minutes or hours, and the waves can keep coming for many hours. If you live, work or visit near the coast, know what to do.

• Coastal Communities
• Visitors
• Families

Know the warnings

• Natural warnings: a strong or long earthquake near the coast, a loud roar from the ocean, or the sea suddenly pulling back far from shore. Move to high ground immediately without waiting for an official alert.
• Official warnings: sirens, wireless emergency alerts, NOAA weather radio, TV and radio, and local officials. A warning means a tsunami is expected or occurring. An advisory means strong currents and dangerous waves are likely. A watch means one is possible.

Prepare

• Find out if your home, work and school are in a tsunami hazard zone using your local emergency management map
• Know the nearest evacuation route and high ground, and practice walking it. Signs mark routes in many coastal areas
• Make a family plan and a go bag. See Family Emergency Plan and Emergency Kit
• Sign up for local alerts
• If you are traveling, ask your hotel about tsunami evacuation

When a tsunami threatens

• Go on foot if you can. Roads jam quickly. Move inland and uphill, away from the water, as far and as high as officials recommend.
• Do not go to the beach to watch the waves or get photos.
• Follow evacuation routes, and help children, older people and neighbors who need assistance.
• If you cannot get out of the zone in time, go to the highest floor of a sturdy, tall building as a last resort, if officials recommend vertical evacuation.
• If you are on a boat in deep water, stay offshore if told to by authorities; in a harbor, follow harbor instructions.

After

• Stay away until officials give the all-clear. Waves can arrive over many hours, and later ones can be larger.
• Avoid flooded areas, damaged buildings, downed power lines and debris. See Downed Power Lines.
• Use text messages instead of phone calls to keep lines free. Check in with family.
• Do not drink floodwater or tap water until it is declared safe. See Disaster Cleanup.

Last updated: October 8, 2026