Millions of Americans across the country are on alert for a severe weather outbreak as violent, long-track tornadoes with damaging winds of up to 80 mph and large hail are expected across the Midwest and South with the cross-country storm moving east.

Violent tornadoes ripped through parts of the U.S., wiping out schools and toppling semitractor-trailers in several states.

The threat of tornadoes moved east into the Mississippi Valley and the south on Saturday, just a day after a massive storm in several central states.

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.