By Steve Murphy, NewsRadio 830 WCCO

MINNEAPOLIS (WCCO) – An expert says the tornadoes that struck north Minneapolis and Joplin, Mo. on Sunday should dispel a popular myth about twisters and big cities.

University of Minnesota professor Ken Blumenfeld, an expert on urban tornadoes, says there’s no evidence that cities give off heat shields, repelling twisters.

“There’s no real evidence at all that tornadoes avoid major cities or downtowns,” he said. “There’s actually a higher frequency — or at least as high a frequency — of tornadoes in major cities including downtown areas than there would be on a per-unit area basis for, say, rural areas”.

In fact, says Blumenfeld, a dozen or so tornadoes have struck large cities in the past 15 years.

WCCO’s John Williams Interviews Ken Blumenfeld