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.

The largest number of deaths, 12, were in Missouri, mostly in Wayne County. Eight deaths were reported in Kansas after a 50-vehicle collision during a "severe dust storm," and six deaths were reported in Mississippi following multiple reported tornadoes.

At least 30 people died as violent weather swept the country on Friday and Saturday, and the threat isn't over.