A high fire danger prompted the National Weather Service to issue a Red Flag Warning for many Green Country counties on Sunday.
That warning expired at 6 p.m, but not before fires spread across the state.
Southwest of Bartlesville in Osage County, several fire departments were called out to battle a fire that started on Hughes Ranch. The Ochelata Fire Department says the fire burned about 4,000 acres in rugged terrain. The fire chief says crews were battling winds up to 40 miles per hour.
"The humidity was low, I think it was like 15 earlier, so especially with that wind, well, you can see how the conditions are and it just took off," OFD Chief Kelly Nissen said.
Crews still are monitoring for flareups. They don't know what sparked the fire.