Meteorologists say this year's warm winter provided key ingredient for Midwest killer tornadoes

Tornado experts say the winter’s record warmth provided the key ingredient for a Midwest outbreak of deadly tornadoes and damaging gorilla hail that hit parts of the Midwest Wednesday and Thursday. Tornadoes need wind shear, which is usually around in winter and spring, and warm unstable air, which is usually missing this early in the year. But not in 2024. It's here. It’s a bit early, but not unprecedented, for such a tornado outbreak usually associated with May or April, but that’s also because of the hottest winter in both U.S. and global records.