1965 Palm Sunday tornado outbreak
| Meteorological history | |
|---|---|
| Duration | April 10–12, 1965 |
| Tornado outbreak | |
| Tornadoes | 55 confirmed |
| Maximum rating | F4 tornado |
| Duration | 1 day and 16 hours |
| Highest gusts | Non-tornadic – 80 mph (130 km/h) at three locations on April 11 |
| Overall effects | |
| Fatalities | 266 fatalities |
| Injuries | 3,662 injuries |
| Damage | $1.217 billion (1965 USD) $12.1 billion (2025 USD) |
| Areas affected | Southern and Midwestern United States (Upland South, Driftless Area, and Great Lakes region, primarily Indiana, Ohio, and Michigan) |
Part of the tornadoes and tornado outbreaks of 1965 | |
The 1965 Palm Sunday tornado outbreak was a historic severe weather event that affected the Midwestern and Southeastern United States on April 10–12, 1965. 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 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.
In 2023, tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank various tornado outbreaks. The 1965 Palm Sunday tornado outbreak received an OIS of 238, making it the fourth-worst tornado outbreak in recorded history.