Not much on that yet. Most of the news coverage is centered around Greenfield, as that community suffered extensive damage & multiple fatalities.
This is the only bit I have found :
The storm also damaged several wind turbines in southwest Iowa. In Adams County, at
least three 250-foot wind turbines were nearly snapped in half, with at least one catching fire.
A spokesman for MidAmerican Energy Company, which owns and operates several wind farms across the state, confirmed that the Adams County turbines are not owned or operated by MidAmerican. The company does, however, own several turbines that were severely damaged in Adair County.
Wind farms are built to withstand tornadoes, hurricanes and other powerful winds. According to the U.S. Department of Energy, turbines are designed shut off when winds exceed certain thresholds, typically around 55 mph. They also lock and feather their blades, and turn into the wind, to minimize the strain.