Could a Tsunami Happen in The United States? | A History of Destruction When You Least Expect It

August 19, 2021 3 min read

tsunamis in the united states

Large tsunamis have struck the United States before, and they will definitely do so again.

Although a tsunami impacting the US mainland may seem unlikely, scientists agree that planning is essential because it will happen — it's only a matter of when.

What are Tsunamis?

The word "tsunami" is originally a Japanese word, but today it's commonly used in English.

Tsunamis are massive ocean waves triggered by earthquakes, underwater landslides, volcanic eruptions, or asteroids.

These waves rush onshore like a rising tide with strong currents.

Tsunamis travel 20-30 miles per hour with waves 10-100 feet high.

They cause flooding and disrupt transportation, power, communications, and the water supply.

It's a general rule that once you see the tsunami, it's too late to avoid it.

Even minor tsunamis (6 feet in height, for example) have tremendously strong currents that can take someone off their feet.

Tsunami waves can last for several hours due to complicated interactions with the coast.

Tsunamis can strike any shoreline on the planet, and they can have an impact thousands of miles away from where they originated.

They may be rare, but the havoc they produce makes them a dangerous natural force.

The History of Tsunamis in the United States

history of Tsunamis in USA

According to the National Geophysical Data Center, large and small tsunamis have affected the North American and United States shores with considerable frequency — and sometimes with lethal intensity — since the late 1600s.

More than 30 tsunamis have been documented in Hawaii alone since 1811.

In Alaska, there have been as many as 16 tsunamis reported since 1853.

Major earthquakes in the Pacific have caused the majority of the almost 30 tsunamis recorded along the West Coast since 1812, and six tsunamis have been recorded in Puerto Rico and the US Virgin Islands since the late 1600s.

One of the largest most devastating tsunamis that Hawaii has experienced was in 1946. It originated from an earthquake along the Aleutian subduction zone. The wave heights hit a maximum of 30 - 50 feet tall and killed 159 people.

The United States Tsunami Warning System

emergency tsunami warning system

The NOAA Tsunami Program runs the U.S. Tsunami Warning System.

They operate two tsunami warning centers, which are staffed 24 hours a day, 7 days a week. This includes tracking tsunamis and the earthquakes that trigger them in order to send out timely and accurate tsunami warnings.

NOAA's capacity to execute this critical job is dependent on its ability to identify tsunamis rapidly, which is accomplished by a network of advanced observation devices.

If an earthquake fits certain requirements, the warning centers send out U.S. communications (alerts) to emergency managers, other officials, the news media, and the general public via different means.

There are four levels of tsunami alerts in the United States: Information Statement, Watch, Advisory, and Warning.

When the centers issue Tsunami Warnings, they are broadcast through local radio and television, wireless emergency alerts, NOAA Weather Radio and NOAA websites

Preparing for a Tsunami in the United States

According to catastrophe experts, planning is critical since a tsunami will hit a U.S. shore at some point — it's only a matter of when.

The earthquake alone will bring down infrastructure such as buildings and bridges, and the tsunami that follows will bring down even more.

Self-reliance is necessary during water disasters more than some other emergencies because floods render useless traditional tactics for aiding citizens in crisis.

For example, floods hinder first responders from driving vehicles to a rescue situation.

Although out of all Earth’s natural hazards tsunamis are among the most infrequent and most are small and nondestructive, tsunamis pose a major threat to coastal communities. People who live, work, or play at the coast should prepare for a tsunami.

Prepare Now

  • Learn about the tsunami risk in your area if you live near or frequently visit a coastal area. Maps with evacuation zones and routes are available in some at-risk localities. Inquire about community plans if you are a guest.
  • Know and rehearse your community's evacuation plans, as well as your routes to and from work, school, and recreation. Choose a shelter that is at least one mile inland and 100 feet above sea level.
  • Create an out-of-state contact for your family's emergency communication plan. Make a plan for where you will meet if you become separated.
  • Become a member of your community's warning system. Emergency notifications are also provided through the Emergency Alert System (EAS) and the National Oceanic and Atmospheric Administration (NOAA) Weather Radio. Sign up for regular updates from the Centers for Disease Control and Prevention about COVID-19 (CDC).
  • Consider earthquake insurance with a National Flood Insurance Program flood insurance coverage (NFIP). Flood and earthquake damage are not covered by standard homeowner's insurance.