At least 12 fatalities have been reported in Missouri, according to the Missouri State Emergency Management Agency. The deaths come as a massive storm system moving across the country unleashed winds that damaged buildings, whipped up deadly dust storms and fanned more than 100 wildfires.

The most dangerous threat was in parts of Louisiana and Mississippi, where intense long-duration tornadoes were striking on Saturday, forecasters said.

The National Weather Service issued tornado watches for more than 2 million people on Saturday. An "outbreak" of tornadoes and severe thunderstorms is expected through Saturday night in Alabama, Mississippi, Louisiana, western Georgia, southern Tennessee, the Florida Panhandle and southern Arkansas.

A severe storm system capable of producing tornadoes, including long-track, strong wind gusts over 70 mph and large hail is causing damages and power outages across Alabama.