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

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.

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. In the latest tally of the destruction,

Deadliest twister in recorded U.S. history The deadliest twister in recorded U.S. history struck 100 years ago Tuesday, touching down in southeastern Missouri and tearing up everything in its 219-mile (352-kilometer) path for nearly four hours through southern Illinois and into Indiana.

Multiple deadly tornadoes tore through the Midwest on Friday, killing at least 16 people. Why It Matters. The month of March traditionally marks the beginning of tornado season in