Unconfirmed death tolls have gone as high as 15.
The half-mile-wide twister blew through the southern Oklahoma town of 5,000 people, leaving 14 others injured. Tens of thousands of utility customers in Oklahoma have also been left without power.
The National Weather Service has confirmed tornadoes touched down in Lone Grove, Edmond and northern Oklahoma City.
A small tornado may have touched down in Colleyville, a suburb of Fort Worth, last night. Two homes suffered major damage.
National Weather Service investigators are spending the morning looking for evidence a tornado was involved.