The Palm Sunday tornado outbreak of 1965: Fifty-one tornadoes hit in six Midwestern states, killing 256 people.
On April 10–12, 1965, a devastating severe weather event affected the Midwestern and Southeastern United States. The tornado outbreak produced 55 confirmed tornadoes in one day and 16 hours. The worst part of the outbreak occurred during the afternoon hours of April 11 into the overnight hours going into April 12. The second-largest tornado outbreak on record at the time, this deadly series of tornadoes, which became known as the 1965 Palm Sunday tornado outbreak, inflicted a swath of destruction from Cedar County, Iowa, to Cuyahoga County, Ohio, and a swath 450 miles long (724 km) from Kent County, Michigan, to Montgomery County, Indiana. The main part of the outbreak lasted 16 hours and 35 minutes and is among the most intense outbreaks, in terms of tornado strength, ever recorded, including at least four "double/twin funnel" tornadoes. In all, the outbreak killed 266 people, injured 3,662 others, and caused $1.217 billion (1965 USD) in damage.