Communities across Missouri, Illinois, and Indiana were devastated by the deadliest and longest-running tornado ever recorded a century ago. Here's what happened.

Tornadoes whipped through Missouri on Friday night, ripping apart homes, businesses, and the electrical system. Gov. Mike Kehoe’s Office says at least 12 people have been killed and one person is still missing from the severe weather.

The meteorological agency said: "If you live in these areas, get to the sturdiest structure you have access to and remain in place until the storms pass." Mike Kehoe, governor of Missouri - where the 11 deaths were reported across four south-easterly counties - said the state had been "devastated by severe storms and tornadoes,

"The scale of devastation across our state is staggering," Missouri Gov. Mike Kehoe said. "While we grieve the lives of those lost, we are also focused on action."

In some extreme cases, thunderstorms can spawn a derecho, a long-lived windstorm with gusts over 100 mph, strong enough to cause widespread destruction. If a severe thunderstorm warning mentions damaging winds or a derecho, take cover immediately—just as you would for a tornado.

The dynamic storm from Friday through Sunday had earned an unusual “high risk” designation from weather forecasters.

The number of fatalities increased after the Kansas Highway Patrol reported eight people died in a highway pileup caused by a dust storm Friday in Sherman County. At least 50 vehi

The most fatalities as of Saturday morning were in Missouri, authorities said, with an estimated 11 people killed.