Indiana's relatively quiet season mirrors the national weather scene, which had been largely quiet until an outbreak of 10 tornadoes in Texas Wednesday night. The National Severe Storms Laboratory in Norman, Okla., reports there were 197 tornadoes rated EF1 or stronger nationwide from May 2012 to April 2013, the lowest number since at least 1954. The previous lows were 247 from June 1991 to May 1992 and 270 from November 1986 to October 1987.
"It's pretty astounding, especially since we had one of the most active tornado periods on record just the year before," said David Call, an assistant professor of geography and meteorology at Ball State University.
Indiana had a total of 10 tornadoes during that May 2012 to April 2013 four of which were rated EF1. The others were all EF0.
The relative calm comes less than two years after a national record was set for most EF1 or stronger tornadoes in a 12-month, with 1,050 from June 2010 to May 2011.
Call said the drought that hit the country last year helped keep the number of tornadoes down, while this year has benefited from strong cold fronts from central Canada that have kept warmth and moisture from the Gulf of Mexico away.
"There were still frost and freeze advisories out just earlier this week," he said.
Call is in Texas with eight Ball State students chasing storms as part of a class. The group saw at least two of the tornadoes that struck the towns of Cleburne and Millsap and may have caught a glimpse of the tornado with wind speeds of between 166 and 200 mph that hit Granbury.
"I couldn't see it because I think we were blocked by curtains of rain. But then our students were looking at pictures afterward and they showed my one picture and they might have got a glimpse of it," he said. "It was a pretty dramatic day for us."
Greg Carbin, a meteorologist with the weather service's Storm Prediction Center in Norman, Okla., said tornado seasons are difficult to predict because there are so many factors involved. In 2010, Indiana had no tornadoes in the first five months of the year but finished with 27, which is above the yearly average of 21.6.
"There's just dramatic variability from one year to the next. It really only takes one very productive weather system with the right conditions and the right ingredients to bring that number up pretty high. In the absence of that, you're just not going to have that high number. It doesn't occur," he said. "But when a powerful weather system moves through, you can get half a dozen tornadoes or a dozen tornadoes even with one event."
The lack of tornadoes doesn't necessarily mean a cost savings for the state in terms of responding to disasters, said John Erickson, spokesman for the Indiana Department of Homeland Security. He said the department doesn't have a separate fund for responding to tornadoes; instead, its emergency funding covers other weather disasters such as flooding as well as responses to hazardous materials, plane crashes and law enforcement situations.
Call cautioned that the tornado season is far from being over.
"There's still plenty of time. For Indiana, June and July are often the biggest months," he said. "But it's been good we haven't seen much in the last year."