Minnesota has experienced its quietest tornado year since 1989, with six so far this season.

That's been the one benefit of a spring that ran cooler than normal well into June, with few blasts of warm, moist air from the south and storm fronts that frequently have weakened as they've moved into Minnesota, said Todd Krause, warning coordination meteorologist for the Twin Cities office of the National Weather Service.

Minnesota sees an average of 27 tornadoes in a season. In 2010, the state's 113 were the most in the nation.

Tornado chaser Tim Purington of Hammond, Wis., who shoots video for the Weather Channel and Fox 9 news, said he's traveled only 5,000 miles this summer when he might have rambled over 30,000 in a normal summer.

While August brings cooling that further limits tornado formation, Minnesota had fatal tornadoes on Aug. 24, 2006, in Kasota and on Sept. 16, 2006, in Rogers. "We could still wind up with a bunch," Krause said. "All it takes is one day."

bill mcauliffe