Tsunami Evacuation Tips
A tsunami is a series of waves most commonly caused by an earthquake beneath the sea floor. As tsunamis enter shallow water near land, they increase in height and can cause great loss of life and property damage where they come ashore.
Recent research suggests that tsunamis have struck the Washington coast on a regular basis. They can occur at any time of the day or night, under any and all weather conditions, and in all seasons. Beaches open to the ocean, bay entrances, tidal flats, and coastal rivers are especially vulnerable to tsunamis.
What is the difference between a 'distant' tsunami and a 'local' tsunami?
When a tsunami has been generated by a distant earthquake, it will not reach the Washington coast for several hours, and there is time to issue a warning. When a tsunami is generated by a strong offshore earthquake, its first waves would reach the outer coast minutes after the ground stops shaking. Feeling an earthquake could be your only warning!
If you feel the ground shake, evacuate inland or to high ground immediately! A wave as high as 20 feet could reach many coastal areas within 30 minutes of the quake. Remember - the first wave is often not the largest; successive waves may be spaced many minutes apart and continue to arrive for several hours. Return only after emergency officials say it is safe.
If you notice a sudden drop or rise in sea level, move to high ground or inland immediately.
If you are inside and hear a broadcast or NOAA Weather Radio alert; or if you are outside and hear an AHAB alert signal follow the instructions provided.
What do the alerts mean?
Tsunami Warning - A tsunami warning is issued when a potential tsunami with significant widespread inundation is imminent or expected. Warnings alert the public that widespread, dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after arrival of the initial wave. Warnings also alert emergency management officials to take action for the entire tsunami hazard zone.
Tsunami Advisory - A tsunami watch is issued to alert emergency management officials and the public of an event that may later impact the watch area. The watch area may be upgraded to a warning or advisory — or canceled — based on updated information and analysis. The public should prepare to take action.
Tsunami Watch - A tsunami advisory is issued due to the threat of a potential tsunami that may produce strong currents or waves dangerous to those in or near the water. Coastal regions historically prone to damage due to strong currents induced by tsunamis are at the greatest risk. The threat may continue for several hours after the arrival of the initial wave, but significant widespread inundation is not expected for areas under an advisory.
Tsunami Information Statement - A tsunami information statement is issued to inform emergency management officials and the public that an earthquake has occurred, or that a tsunami warning, watch or advisory has been issued for another section of the ocean. In most cases, information statements are issued to indicate there is no threat of a destructive tsunami and to prevent unnecessary evacuations as the earthquake may have been felt in coastal areas.
Washington state coastal areas have been mapped to identify the tsunami hazard zones and evacuation routes. You can download a map for your area from the Tsunami Hazard section. Areas of higher ground are identified on these maps. When you evacuate, go to the nearest high ground - at least 50 feet above sea level if possible.
If you do not have time to travel to high ground, but are in a multi-story building, go to an upper level. If you are on the beach and unable to get to high ground, go inland as far as you can.
Tsunami evacuation routes were developed to guide coastal residents and visitors to safer locations when car evacuation is possible. Evacuation signs have been placed along the main roads to direct motorists to higher ground. In some places, there are may be more than one way to reach safer areas. These routes are marked with multiple signs showing additional options for evacuation. You will need to know the evacuation routes for your area.
Getting to higher ground
Car evacuation may not always be possible. If an earthquake occurred damage to roads, debris or downed power lines may make the roads impassible. If this is the case, do not try to follow the evacuation routes. Evacuate on foot directly to the nearest high ground. Avoid lakes and wetlands, which are prone to flooding and liquefaction during aftershocks.
Take action now and be prepared! The steps you take today can improve your chances of survival and your comfort. This is especially true for a tsunami event when there may be only minutes to move to a safer place. The links below provide simple, step-by-step activities you can take to ensure your safety.