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

"Get to the sturdiest structure you have access to and remain in place until the storms pass," the NWS told residents in Alabama on Saturday night, when multiple tornado warnings were issued. At least 250,

Large and destructive tornadoes are carving paths of destruction across the South for the second day in a row.

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.