GREENFIELD, Iowa (KCRG) – On May 21st, 2024, an EF 4 tornado spun a trail of destruction through Greenfield. Nearby wind turbines were bent in half and set on fire. Dr. Bill Gallus, a Professor of Meteorology at Iowa State University, told KCRG-TV, that in addition to the hot and humid air, which fueled the storms on that fateful Tuesday, a short distance between the storms may have strengthened the Greenfield tornado.

Dr. Gallus said there was another tornado that was only passing maybe 5 miles to the northwest of the Greenfield tornado, [and while their] instruments [were] not nearly close together enough to understand exactly what happened, he thinks there was probably some type of interaction happening with those two tornadic storms.

Engineers design wind turbines to withstand wind speeds up to 140 miles per hour. Meteorologist and engineer Tim Marshall kept that in mind as he watched video of the Greenfield tornado. Marshall said they would normally anticipate the turbine blades would shred, and that they would come apart in pieces and that’s exactly what happened. The tower which supports the turbine nacelle and blades was stronger.

Now, scientists are using their knowledge of meteorology and wind turbines to upgrade the EF Scale. Engineers such as Dr. Partha Sarkar, a professor of Aerospace Engineering at Iowa State University, are working to better understand how tornado winds impair wind turbines.