U.S. flag An official website of the United States government.

dot gov icon Official websites use .gov

A .gov website belongs to an official government organization in the United States.

https icon Secure websites use HTTPS

A small lock or https:// means you’ve safely connected to a .gov website. Share sensitive information only on official, secure websites.

What is a tidal wave?

A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth.

The  NOAA San Francisco Tide Station, in operation for more than 150 years.

The rise and fall of the tides play an important role in the natural world and can have a marked effect on maritime-related activities. The image aboves shows the NOAA San Francisco Tide Station, in operation for more than 150 years.

A tidal wave is a regularly reoccurring shallow water wave caused by effects of the gravitational interactions between the Sun, Moon, and Earth on the ocean. The term "tidal wave" is often used to refer to tsunamis; however, this reference is incorrect as tsunamis have nothing to do with tides.