Entire neighborhoods have become waterfront properties, with high water swamping many roads. More than a foot-and-a-half of water covered streets in Portland. Some public buildings have been closed due to flooding.
Heavy rain and melting snow is to blame for all the water. Parts of Ohio and Indiana received up to 3 inches of rain and some hail overnight Sunday. Crews in boats rescued nearly 30 people, including a group trapped in a mobile home park in western Ohio, said Mike Robbins, Mercer County's emergency management director.
Elsewhere, a tornado hit Celestine, Ind., a town of about 250, and damaged two homes and a double-wide trailer, the weather service said. A tornado that touched down near the small town of Ingalls, northeast of Indianapolis, damaged two homes, barns and a trailer.
Officials say it will be several days before flood waters recede.
The Associated Press contributed to this report.