Tsunamis may seem like rare disasters, but in the U.S., three major regions are at real and growing risk: the Pacific Northwest, East Coast, and Gulf Coast. These massive waves, triggered by underwater earthquakes, landslides, or volcanic eruptions, move fast—up to 500 mph—and strike with devastating force once they reach shore. Millions of Americans live within range of potential impact zones, unaware of how little time they’d have to react in a real event.

The Pacific Northwest faces the greatest danger, sitting atop the volatile Cascadia Subduction Zone. A rupture here could trigger a magnitude 9.0+ quake, unleashing waves as high as 100 feet and sinking entire coastal towns within minutes. Evidence of past disasters—like “ghost forests” and Native oral histories—suggests we’re overdue. Scientists estimate a 10–14% chance of a megaquake in the next 50 years.

The East Coast and Gulf Coast aren’t safe either. Tsunamis from the Caribbean fault zone or underwater landslides could strike Florida and surrounding states with little warning. Past events in Puerto Rico and the Dominican Republic have killed thousands. Rising sea levels and climate change only increase the danger, making future waves more powerful and flooding more widespread.

Warning systems help—but instinct and preparation save lives. If you feel an earthquake near the coast, don’t wait for sirens. Run to higher ground. Know your escape routes. Keep a go-bag ready. Scientists are racing to improve detection, but the truth remains: another wave will come. The only question is—will you be ready?