Tidal waves, more accurately called tsunamis, have hit the U.S. several times, most often in Hawaii or Alaska.
However, California has been hit a couple of times in the last hundred years as well. The most deadly, but surprisingly obscure, tsunami to strike the contiguous U.S. took place in 1964.
A record-shattering earthquake in Alaska was the catalyst for a series of huge waves—at least one (in Shoup Bay, Valdez Inlet) officially measured 67 meters high—that crashed into the western U.S. coast.
All in all, 120 people lost their lives throughout Canada, Alaska, Oregon, Washington, and California.
The deaths included 106 Alaskan residents and four campers on a beach in Newport, Oregon. Crescent City, California, was engulfed in a wave and 11 people were killed. Another man in Klamath, California, drowned.
In 1946, Hawaii was caught relatively unaware by a devastating tsunami.
One hundred and seventy-three people were killed, prompting the foundation of the Pacific Tsunami Warning System (PTWS), a system that watches for tsunamis and attempts to give timely warnings of their approach to all U.S. regions in the Pacific.