The National Weather Service says a strong, fast-moving storm system spawned a tornado that struck near midtown Tulsa, and possibly two other tornadoes.
Emergency Medical Services Authority spokeswoman Kelli Bruer says two people suffered life-threatening injuries and 11 others were transported to hospitals.
St. Francis Hospital spokeswoman Lauren Landwerlin told the Tulsa World that up to 30 people were treated at the hospital. Landwerlin did not immediately return messages left by The Associated Press, but A city spokeswoman says many people were taken to hospitals by private vehicles.
No deaths are reported.
Weather Service meteorologist Mike Teague says an EF2 tornado, with wind speeds of 111 to 135 miles per hour touched down shortly after 1 a.m. Sunday and possibly two other smaller tornadoes touched down later near Inola and Claremore, about 25 miles (40 kilometers) east and northeast of Tulsa.
The storm caused extensive damage in Tulsa and left more than 11,000 customers without power at one point. More than 4,300 remained without electricity Sunday afternoon.