Slow year for tornadoes in Iowa, but season not over yet

The 2010 tornado season in Iowa has blown by without much fanfare.

While many parts of Iowa have been pounded by excessive rain that have spawned flooding problems, 2010 has been a fairly uneventful year for tornadoes in Iowa. But state climatologist Harry Hillaker cautions the season isn't over yet.

Through August, Iowa's unofficial tornado count stood at 36, which was lower than the yearly average of 48, said state climatologist Harry Hillaker of the state Department of Agriculture and Land Stewardship. At the same, he said, Iowa normally sees about three tornadoes after Sept. 1 and has had years where a dozen twisters have touched down after that date.

“For us, it's been very quiet,” said Hillaker. However, he noted that neighboring state Minnesota surprisingly is leading the nation with 122 tornadoes reported through mid-August this year while another border state, Wisconsin, ranked sixth with 59 tornado touch-downs.

“It's just one of those things. There's a huge amount of variability from year to year,” Hillaker said. “That's why there isn't much point in trying to make a tornado outlook. It doesn't necessarily follow regular weather patterns.”

June has been the worst month for tornadoes this year, with dozens injured when an EF4-rated storm battered farmsteads near Sibley with winds of about 200 mph. Earlier that month, an EF2-rated tornado with winds of up to 135 mph destroyed a livestock building and severely damaged a home in Ringgold County.

“For the most part this year, the ones we've had have not been particularly large ones,” said Hillaker, who noted, however, that “they're not small if they happen in your back yard.”

This year marked the second straight year of below-average tornado activities, but 2008 was a very active year with 105 tornadoes that included deadly twisters that swept through Parkersburg and a Boy Scout camp in western Iowa.

The most tornadoes in one year occurred in 2004. with 120 reported touch-downs, while the low year was 20 in 1996 – a year when none occurred in July, Hillaker said.

Number of tornadoes reported in Iowa

• 2010      36 (through Aug. 31)
• 2009      25
• 2008      105
• 2007      42
• 2006      38
• 2005      44
• 2004      120

Number of tornadoes reported in Iowa

• 2010      36 (through Aug. 31)
• 2009      25
• 2008      105
• 2007      42
• 2006      38
• 2005      44
• 2004      120

Source: State Climatologist Harry Hillaker

DATABASE: Tornadoes in Iowa

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