The dynamic storm from Friday through Sunday had earned an unusual “high risk” designation from weather forecasters.

In some extreme cases, thunderstorms can spawn a derecho, a long-lived windstorm with gusts over 100 mph, strong enough to cause widespread destruction. If a severe thunderstorm warning mentions damaging winds or a derecho, take cover immediately—just as you would for a tornado.

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.

Tornadoes killed at least 33 people across several states in the U.S. Midwest and Southeast on Saturday night, CNN reported. Missouri reported 12 fatalities spanning five counties, the state's highway patrol posted on X.

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.

At least 26 people have been killed in a monster storm sweeping across much of the U.S. People were killed in tornadoes in Missouri and in a Kansas dust storm.