Fewer tornadoes during drought year

With all the worry this summer about the hot, dry weather, hardly a word was said about those usual staples in Iowa - severe thunderstorms and tornadoes.

For good reason.

State Climatologist Harry Hillaker reports the state is on track to record the fewest tornadoes in almost 50 years.

“It's been an extremely quiet year.” Hillaker said. “Fewer thunderstorms means there's fewer opportunities to get tornadoes.”

Barring a twister forming out of the violent weather predicted for today, Iowa will have recorded just 16 tornadoes.

“Say that number holds up, that is the lowest total since 1963,” Hillaker said.

“(But) back then the records weren't remotely as complete as they are today,” he added, so it's likely there were a few more tornadoes that year.

Some other recent years with few tornadoes: 25 in 2009, 24 in '97, 20 in '96. There were 49 in the drought year of 1988, including an outbreak of 25 on Mother's Day.

The yearly average for past 33 years is 47, with annual totals ranging from 16 to 120.

There have been no Iowa tornadoes since May 24.

“For the most part it's been fairly weak ones, Hillaker said. The most powerful tornadoes this year were three rated F3 on Fujita scale which means they had winds of 158 to 206 mph.

Peak tornado season in the upper Midwest is late spring to early summer, although tornadoes have occurred every month. A weaker jet stream in the fall makes conditions less likely for tornado formation.

“As always, it can change in a very short time,” Hillaker said.