Knowing what to do during a tsunami starts with recognizing warning signs and knowing your local evacuation route.
If you are in an exposed coastal area and authorities order an evacuation, go immediately to the designated safe area. A strong or long earthquake, a sudden change in sea level, or an unusual roar from the ocean can also warn of a tsunami. When you notice these natural warning signs, do not wait for a phone alert: evacuate as soon as it is safe to move.
This guide explains what to do during a tsunami and how to prepare a safe evacuation. Routes, shelters, and risk areas vary by location. Check the official plan for the place where you live or are visiting.
Tsunami warning signs
Warnings can come from official channels or from your surroundings. Near the coast, watch for these signs:
- A strong earthquake or shaking that lasts a long time. You do not need to know its magnitude before acting. The Japan Meteorological Agency also warns about weak but prolonged shaking.
- A sudden change in the ocean: an unusual withdrawal of water or a rapid rise.
- An unusual roar from the ocean.
You do not need to notice every sign. Do not wait to see a wave: the water can arrive quickly with dangerous currents. If an official warning is issued, follow its instructions even if you did not feel an earthquake.
What to do during a tsunami, step by step
1. Protect yourself during the earthquake
While the ground is shaking, protect yourself from falls and objects that could strike you. Read our guide to what to do during an earthquake. Once you can move safely, leaving the inundation zone becomes the priority in an exposed coastal area.
2. Follow the local evacuation route
Move inland or to higher ground using official signs and evacuation maps. There is no single distance or elevation that guarantees safety along every coastline. Your destination should be outside the mapped inundation zone or an approved refuge.
If you are visiting, ask your accommodation about the route and safe destination. Vertical evacuation buildings are an option only where the local plan provides for them. Do not assume that any tall building is a suitable refuge.
3. Avoid delays and keep routes clear
Do not go to the beach to watch, record video, or collect belongings. Evacuate on foot when possible and when the local plan recommends it, to reduce traffic congestion. Some places require other arrangements: follow the instructions for your location.
Take your emergency supplies only if they are immediately accessible and do not delay your departure. Help children and people who need support when you can do so without endangering the evacuation. Stay away from river mouths and follow designated routes: tsunami water can travel into rivers and estuaries.
4. Stay in the safe area
A tsunami can bring several waves, and the first may not be the largest. Receding water or a quiet interval does not mean the danger has passed. Follow official information and do not return until local authorities authorize it.
If you are outside the risk area
Stay away from the coast. If you are already outside the inundation zone, remain there unless authorities direct otherwise. Going into an exposed area to find someone can put more people at risk and obstruct routes. Agree on a meeting point and a way to communicate beforehand.
How to prepare before an emergency
- Check the official inundation map and routes from your home, workplace, or accommodation.
- Practice the route and plan assistance for people with limited mobility.
- Learn the school’s evacuation procedure and avoid improvised pickups that could interfere with it.
- Keep accessible supplies with water, necessary medication, a flashlight, and a way to receive information.
- Identify official warning channels and a family contact outside the area.
When is it safe to return?
A canceled warning does not replace local permission to return. Damage, debris, fallen power lines, or closed roads may remain. Follow restrictions and stay out of damaged buildings. Our guide to what to do after an earthquake covers further precautions following the shaking.
EarthSentra’s tsunami monitoring provides additional information. It does not replace emergency warnings and should never delay an evacuation.
Official sources
- National Weather Service: during a tsunami.
- National Weather Service: before a tsunami.
- National Weather Service: after a tsunami.
- SENAPRED: tsunami guidance.
- Japan Meteorological Agency: tsunami information and warnings.
- FEMA / Ready.gov: tsunami preparedness fact sheet.
- U.S. Tsunami Warning Centers: frequently asked questions.
