At least five people are killed and 35 are injured as a strong tornado devastates the town of Greenfield, Iowa, United States. A Doppler on Wheels unit records a wind gust of between 250 mph (400 km/h) and 290 mph (470 km/h) over Greenfield, the strongest winds recorded inside a tornado by a mobile weather radar since the 2013 El Reno tornado, equivalent to EF5 intensity on the Enhanced Fujita scale.