Tsunamis, also known as seismic sea waves, are most common along the Pacific coast, but can strike anywhere along the U.S. coastline. Tsunamis are enormous waves caused by an underground disturbance such as an earthquake. They can move hundreds of miles per hour, and hit land with waves topping 100 feet in height.

• Understanding the difference between the terms that identify a tsunami hazard: advisory, watch and warning. For a detailed explanation of these terms, see http://www.fema.gov/areyouready/tsunamis.shtm.
• Plan to act quickly. If you are in coastal waters and notice a dramatic recession of water from the shoreline you should heed nature's warning that a tsunami is approaching.
• Move inland immediately and do not return to the flooded and damaged areas until officials say it is safe to do so.
• If you are in coastal waters and notice a dramatic recession of water from the shoreline you should heed nature's warning that a tsunami is approaching.
• Visit NOAA Watch for more weather-related information.