The death toll was expected to grow, they said. About 200 people had been injured.
The tornado touched down near Henderson, Ky., and jumped the Ohio River into Indiana at around 2 a.m.
At least 12 people were killed in the Eastbrook Mobile Home Park in Evansville, said Annie Groves, chief deputy coroner for Vanderburgh County. She said she expected the death toll to grow because an unknown number of people were believed still trapped in debris at the park, which has about 350 homes.
"They were in trailer homes, homes that were just torn apart by the storm, so they're just now getting in there trying to find people," Groves said. "It's just terrible."
Indiana homeland security spokeswoman Pam Bright said four other people were confirmed dead in adjoining Warrick County, east of Evansville, where the Ohio River city of Newburgh was struck. She said a fifth person initially reported as dead was alive but in critical condition.
Bright said about 100 homes were destroyed and 125 others were damaged at the mobile home park.
It sounds like it could have alot worse.