Unusually vicious and damaging weather across multiple U.S. states spawned violent tornadoes, blinding dust storms and fast-moving wildfires over the weekend, leaving at least 39 people dead.

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.

Violent tornadoes ripped through parts of the U.S., wiping out schools and toppling semitractor-trailers in several states.

The weakening but still volatile weather system was moving Monday into the US Southeast and Mid-Atlantic, bringing thunderstorms, hail, damaging winds, and the potential for more tornadoes.

The most fatalities were in Missouri. Forecasters warned that tornadoes, hail and violent winds continue to threaten states in the Deep South, from Louisiana to Georgia.