The April 1, 1946 Aleutian Island earthquake tsunami that killed 165 people in Hawaii and Alaska resulted in the creation of a tsunami warning system (specifically the Pacific Tsunami Warning Centre), established in 1949 for Pacific Ocean countries. The tsunami in question is known in Hawaii as the "April Fools' Day Tsunami" due to people drowning because of the assumptions that the warnings were an April Fools' prank.
People died due to an actual disaster, and as a result of this April Fools bullstuff, more people died because many, including Rescue Teams and other Emergency Services, thought it was all a joke. That is the primary reason to out April Fools Day, getting rid of Internet Pranks and Hoaxes is a secondary focus.
