Research explores tornadoes and terrain

Chris Karstens, graduate in geological and atmospheric sciences, explains how he has used the tornado/microburst simulator in Howe Hall to do research about how terrain effects damage caused by wind. 

Thaddeus Mast

Tornadoes: the freight trains of nature.

New research is trying to help understand these seemingly random events of destruction.

Bill Gallus, professor of geological and atmospheric sciences, explains his research.

“One goal is to better understand how tornado winds change as tornadoes go up or down hills and mountains.”

Christopher Karstens, a doctoral student studying under Gallus, has been studying the effects of a deadly tornado that occurred in Alabama almost a year ago, trying to accomplish this goal. This tornado is special in that its path took it through a very hilly and heavily wooded terrain, which had interesting effects on the tornado as well as the winds around it.

“Trees fell in a valley channel that was extending away from where the primary damage spots were, well away from where the tornado actually occurred, but it was connected to it,” Karstens said.

This brought him to start examining aerial photographs of the affected area, looking specifically at the patterns the trees fell in.

“Trees are a very good damage indicator,” Karstens said. “They are very widespread; they’re consistent, and they stick around a while.”

What is meant by ‘they stick around a while’ is that they are not a large focus for cleanup crews, who usually overlook the fallen trees until other, more pressing issues are dealt with.

“People start cleaning up within five minutes. That makes it tough for people who are looking at the damage in a sort of forensic sense,” Karstens said. “It’s not like we can tell people to not clean up their stuff.”

This makes the tree fall important and a key part of the research. But tree fall itself cannot bring about enough information. For that, Karstens made a scale model of the Alabama terrain out of foam and placed it underneath Iowa State’s tornado simulator.

Although the testing is still fairly preliminary at this point, the terrain is appearing to have an effect on the tornado.

“It’s opening my eyes at least, as well as the eyes’ of many others who do similar work, as to what kind of damage patterns to expect in very rough or mountain terrain,” Karstens said. “One of the things that this work re-emphasizes is that tornado-strength winds can extend well away from the actual tornado.”

Although hills have been known to have an effect on tornadoes, little research has been done on the subject.

“There hasn’t been much [research] yet,” Gallus said. “Our work would be the first that is making use of a laboratory simulator, since Iowa State has had the only tornado simulator until recently.”

Since the tornado season of May and June is coming upon us, here are a few parting pieces of advice to help keep you safe.

“In some instances you only have five minutes, so the sooner you respond the better,” Karstens said. “I always urge people into getting an app or sign up for a text message service so they can receive a warning on their phone.”

Gallus offered some age old wisdom on staying safe too.

“Going to the basement is the best thing to do.”