A powerful storm system that tore across the United States in recent days is winding down Monday, but in its wake are devastated communities across states hit with violent tornadoes, wildfires and dust storms spun off by the massive system.

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.

"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,