Your Local Risks · Hazard Guide
Tsunami.
Minutes to move. No second wave of warning.
A tsunami generated by a local earthquake can reach the coast in minutes. The earthquake itself is the warning. Knowing your evacuation zone and route to high ground before it happens is the entire preparedness strategy.
FROM THE FIELD
The ocean pulled back and people walked toward it. That is the pattern that surfaces in account after account from the 2004 Indian Ocean tsunami: the most visible natural warning sign drew people onto the exposed seafloor to look at stranded fish and boats rather than sending them inland. The warning signs this page teaches work only if you have learned them before the water moves. When the ocean does something it has never done in front of you, the correct response is to run from it, not toward it.
Understanding the hazard
Not a wave. A wall of ocean.
A tsunami is not a single breaking wave. It is a series of surges, sometimes described as a rapidly rising tide that does not stop. The water can push inland for hundreds of yards or miles depending on coastal topography, carrying debris, vehicles, and structures with it. The first surge is not always the largest.
Tsunamis are generated by undersea earthquakes, volcanic eruptions, or submarine landslides. In the Pacific Northwest, the Cascadia Subduction Zone is capable of producing a magnitude 9.0 earthquake that could send a tsunami onshore in as little as 15 to 20 minutes. The 1964 Good Friday earthquake in Alaska generated a tsunami that killed people as far away as Crescent City, California.
The critical distinction is between local and distant tsunamis. A local tsunami from a nearby earthquake gives you minutes. A distant tsunami from across the Pacific gives you hours and triggers formal warnings through the Pacific Tsunami Warning Center. For local events, you are the warning system. If the ground shakes hard for 20 seconds or more near the coast, move to high ground immediately.
Know your exposure
U.S. tsunami risk zones
Tsunami risk varies enormously by coastline. If you live, work, or vacation on the coast, know which zone you're in.
Pacific Northwest
Washington, Oregon, and Northern California face the highest risk from the Cascadia Subduction Zone. A full rupture could produce a tsunami reaching coastal communities in 15 to 20 minutes. Some areas have vertical evacuation structures.
Alaska
The most seismically active state in the U.S. Alaska generates more tsunamis than any other state and has the most extensive tsunami warning infrastructure. Coastal communities practice regular evacuation drills.
Hawaii
Exposed to both local and distant tsunamis from across the Pacific basin. Hawaii has a well-established siren warning system and detailed inundation zone maps. Hilo has been struck by destructive tsunamis multiple times.
Atlantic & Gulf
Lower risk but not zero. Submarine landslides, the Canary Islands volcanic flank, and the Puerto Rico Trench all present potential sources. Caribbean communities have the highest exposure on this coastline.
Before it happens
Preparation for tsunami
Map your evacuation route
Walk your route to high ground. Time it. The target is 100 feet above sea level or at least one mile inland on flat terrain. Know at least two routes in case one is blocked. If you live or work in a tsunami zone, this is the single most important thing you can do.
Know vertical evacuation sites
Some coastal communities have designated vertical evacuation structures: reinforced concrete buildings, parking garages, or purpose-built tsunami shelters. If you cannot reach high ground, the third floor or above of a reinforced concrete building may be your best option.
Go on foot
After a major earthquake, roads may be cracked, blocked, or jammed with traffic. Evacuation on foot is often faster and more reliable than driving. A go-bag with shoes, a flashlight, water, and essential medications should be staged near your door.
Learn the warning systems
Wireless Emergency Alerts, NOAA Weather Radio, and local tsunami sirens (where installed). For distant tsunamis, formal warnings provide hours of lead time. For local tsunamis, the earthquake is the warning. Do not wait for sirens. Move.
From the field · Accounts from both the 2004 Indian Ocean and 2011 Japan tsunamis describe people on foot reaching high ground while vehicles were still gridlocked or caught in the surge. Roads crack, bridges fail, and traffic jams form in seconds. The "go on foot" guidance above is grounded in what survivors consistently report working.
The key skill
When to move
If you are near the coast and any of these happen, evacuate immediately to high ground. Do not wait for confirmation.
Strong earthquake lasting 20+ seconds
A long, strong earthquake near the coast is the most reliable natural warning. Drop, cover, and hold during the shaking. The moment shaking stops, grab your go-bag and move to high ground immediately. Do not return until officials give an all-clear.
Ocean suddenly retreats from shore
If the ocean pulls back dramatically, exposing sea floor that is normally underwater, a tsunami surge is likely incoming. This is not the time to investigate. Run inland or uphill immediately.
Official tsunami warning issued
Wireless Emergency Alerts or tsunami sirens mean evacuate now. Move to your predetermined high-ground location. Stay there until officials issue an all-clear. Tsunami surges can continue arriving for hours.
Stay at elevation until all-clear
The first surge is not always the largest. Tsunami waves can arrive in series over several hours. Do not return to low-lying areas until emergency management confirms it is safe. Monitor NOAA Weather Radio or local emergency channels.
From the field · Accounts consistently describe survivors returning to the coast after the first surge to check on homes or help others, then being caught by waves arriving hours later. The danger window is measured in hours, not minutes, and the urge to go back is the specific behavior the all-clear protocol exists to prevent.
Official resources
Where to learn more
Next step
Build your go-bag
Tsunami evacuation happens fast. A staged go-bag with shoes, water, flashlight, medications, and documents means you leave in seconds instead of minutes. The First 72 Hours guide covers what goes in and where to keep it.
First 72 Hours guide"Those who cannot remember the past are condemned to repeat it."
— George Santayana
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