An ISU professor explained Tuesday that the tornado that hit campus Sept. 8 was anything but ordinary.

The F1 tornado took place at an odd time of year for tornados, and lacked the usual pressure characteristics, said Tsing-Chang Chen, professor in geological and atmospheric sciences, in an address to a crowd of nearly 50 ISU students and faculty Tuesday.

The tornado, which touched down near the Science 1 building, brought precipitation and winds reaching 83 mph.

“What we are interested in is not only to define description, it’s also to understand dynamics of the environment to generate tornados,” Chen said.

According to previous Daily staff reports, cleanup was estimated to be about $150,000 after the storm hit, uprooting trees and fences and leaving behind broken windows.

Seven people were injured as a result of the tornado – none were seriously injured.

Chen said May and June are the most common months for tornadoes to occur, along with the highest amount of rainfall. As summer and fall approach, the amount of rainfall decreases.

He said the typical tornado will form when a cold front and warm front intersect. High and low pressures are also present behind these fronts.

Using research from the sensor on top of the Agronomy Hall roof during the storm, Chen discovered the tornado carried high pressures behind both fronts. It also did not fit the typical profile since the tornado took place during a fall month.

Janet Schenck, senior in meteorology, said she noticed how the tornado did not have a stationary front, but instead the warm air formed a warm front.

“This one was actually a little atypical because it happened north of the warm front instead of south of it,” Schenck said.

Chen said it is the university’s duty to research the tornado because Iowa State has a strong meteorology undergraduate program.

“It would be embarrassing if we don’t do that,” Chen said. “You don’t see too many tornadoes touch down and occur inside the campus of the major universities of this country.”