A "hook echo" and tornado as mapped at fine-scale resolution by a Doppler On Wheels (DOW) radar. Image courtesy of the Center for Severe Weather Research. Disclaimer: AAAS and EurekAlert!

Storm chasers with a mobile radar, the Doppler on Wheels (DOW), have recorded some of the strongest wind speeds in a tornado in Greenfield, Iowa. The DOW measured wind speeds as high as 308-318 ...