What nickname is given to the 1946 Aleutian Islands tsunami?

The 1946 Aleutian Islands tsunami is known as the April Fools' Day tsunami. It followed a powerful earthquake near Alaska’s Aleutian Islands on April 1, 1946, a date that helped give the event its memorable nickname.

The earthquake generated a Pacific-wide tsunami, with destructive waves reaching Alaska and Hawaii. At Unimak Island, waves reached roughly 42 meters and destroyed the Scotch Cap Lighthouse, killing all five lighthouse keepers. The tsunami later struck Hilo, Hawaii, where it caused most of the recorded casualties and extensive destruction.

The event was especially important in tsunami science because the earthquake initially appeared less powerful than the waves suggested. Researchers later classified it as a “tsunami earthquake,” meaning its tsunami was unusually large relative to the ground shaking felt locally. The disaster helped prompt the creation of a formal Pacific tsunami warning system.