Twisting Fury: The Science Behind the EF-4 Tornado That Ravaged Iowa

During one of the most active U.S. tornado seasons, a powerful EF-4 tornado devastated Greenfield, Iowa, with winds of 185 mph. The destructive tornado destroyed homes, downed wind turbines and power lines, snapped trees, and shredded roofs.

It’s been one of the busiest U.S. tornado seasons in years. As of May 28, National Weather Service meteorologists have confirmed 875 tornadoes. One of the strongest and most destructive was a powerful twister that formed in southwestern Iowa on May 21, 2024. The tornado drew a line of destruction for nearly 44 miles and cut through the town of Greenfield, Iowa.

The tornado was one of a rash of twisters that formed when a cold front produced a line of strong thunderstorms that tracked through the Midwest. An especially large and tall storm with rotating updrafts (a supercell) produced an EF-4 tornado, which hit Greenfield with peak winds of 185 miles (300 kilometers) per hour.