A deadly tornado outbreak in Dixie Alley, where unique risks like rain-wrapped and nocturnal tornadoes are prevalent, confirmed a rare high-risk weather forecast, leading to at least 40 deaths and emphasizing the area's vulnerability as spring begins.

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.

Meanwhile, the severe weather threat will linger through Sunday from Florida northward into the upper Ohio River Valley, forecasters warned.