What is a tsunami and why should I be concerned about them in coastal areas?


A tsunami (pronounced soo-nahm-ee) — the Japanese word for harbor wave — is a series of huge waves that can be triggered by an ocean disturbance, such as an earthquake or volcano eruption. The waves travel in all directions away from the area of disturbance, much like ripples in a pond after a stone is thrown into it. The waves can travel in the open sea as fast as 600 miles per hour. As the waves approach shallow waters along the coast, they may grow to as much as 100 feet tall, crash into the shore, and cause major destruction.

A tsunami can strike anywhere along the U.S. coastline. The most destructive tsunamis have occurred along the coasts of California, Oregon, Washington, Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands.

 Warning signs that a tsunami may be approaching include:

If you witness these signs — don’t panic! Move to higher ground or into a tall building immediately and stay there. Turn on your radio or television to learn if there is a tsunami warning. Stay away from the beach until officials issue an “all clear.”

You can prepare for a tsunami by developing a family disaster plan and practicing it in advance, much like a fire drill. If you live or vacation near the coast, locate the local evacuation route. While at the beach, discuss what you would do if you saw the warning signs of an approaching tsunami with your family and friends — where would you go for safety? You also can purchase a NOAA Weather Radio All Hazards receiver and prepare a disaster supply kit with food, water and medications to take with you in the event a tsunami does occur.

Sources:  Jenifer Rhoades, NOAA Tsunami Program Manager and FEMA.

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