One of the state's deadliest tornadoes in history, the 1974 Xenia F5 tornado, occurred in Southwest Ohio. How do tornadoes form?

The gravest area hit was Xenia, where an F5 tornado with winds between 261 and 318 mph decimated nearly half of the city. Only one hospital remained, packed with nearly 2,000 people.

The worst tornado in Ohio was about an hour and a half away from Lancaster, the Xenia F5 tornado on April 3, 1974, that took 34 lives.

On May 31, 1985, an unprecedented 44 tornadoes ripped across Pennsylvania, Ohio, New York, and Ontario, Canada. The outbreak produced Pennsylvania's first and only F5 tornado, a violent twister ...