The 1958 Lituya Bay megatsunami occurred in 1958, on July 9, in southeastern Alaska.
An earthquake on the Fairweather Fault triggered a massive rockslide into Gilbert Inlet, a narrow arm of Lituya Bay. The sudden impact displaced a huge volume of water and sent a wave racing up the opposite slope. Evidence left by stripped vegetation showed a maximum run-up of about 524 meters, or roughly 1,719 feet.
That figure describes run-up—the highest elevation reached by the water—not a free-standing wave measured in the open ocean. Lituya Bay’s steep, enclosed geography amplified the local surge, making the event very different from a typical earthquake-generated tsunami traveling across an ocean.
Five people died, including two fishermen whose boat was overwhelmed near the bay entrance. The disaster remains one of the clearest examples of a landslide-generated megatsunami and is frequently described as the highest tsunami run-up ever documented.