A deadly tornado outbreak ripped through Missouri, Illinois, Arkansas and Mississippi overnight Friday, leaving destruction, power outages and tragic loss in its wake.

A quickly-spreading wildfire, fueled by powerful winds, has forced the urgent evacuation of the entire town of Velma, in Stephens County Oklahoma. The Oklahoma Highway Patrol is closing parts of OK-7 to keep people out of danger as flames tear through dry grass.

Numerous significant tornadoes are expected Saturday afternoon and evening, with the highest risk across several states in the Deep South, forecasters say.

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.

After deadly storms scourged the Heartland, volunteers are gathering from across the area to help with relief and recovery efforts.

An "outbreak" of tornadoes and severe thunderstorms is expected through Saturday night in Alabama, Mississippi, Louisiana, and other southern states.