It was one of several thunderstorms that sprang up in southwestern Indiana near Terre Haute and became more severe as they moved northeast toward Indianapolis. National Weather Service meteorologist Mike Ryan said the tornado struck in the afternoon just southwest of Indianapolis and caused extensive damage to at least three homes.
That storm then headed into Indianapolis, where Public Safety Director Troy Riggs said city emergency officials received reports of house and tree damage and downed power lines on the southwest side of the city.
Indiana State Police Sgt. Rich Myers said no injuries were reported. "That's the good news," he said.
The city of Indianapolis opened an operations center to organize its response to the storm, Homeland Security Director Gary Coons said.
"Something hit here. Whether it was straight-line winds or a tornado, something with a lot of wind hit here," Coons told WRTV. "We're just trying to assess and see how much damage there is."
Indianapolis Power and Light Co. reported more than 1,600 customers without service shortly after the storm in a second straight day of storm-related outages in the city.
As the storm moved into the northern suburb of Carmel, Duke Energy reported about 100 customers without power.
Heavy rains accompanying the storms prompted the weather service to issue flash flood warnings for much of central Indiana.