Emergency personnel say about a dozen people have been evacuated from their homes because of wildfire that has burned 37 square miles in rural western Oklahoma.

Woodward County emergency manager Matt Lehenbauer said Tuesday that the fire is 16 miles long. He says no one has been injured and one home is destroyed.

The fire began Monday near Boiling Springs State Park northeast of Woodward and was burning northeastward. The cause of the fire hasn't been determined.

Oklahoma Forestry Services spokeswoman Michelle Finch-Walker says the agency is using bulldozers and road graders to clear vegetation to assist in firefighting efforts, and will use helicopters to drop water on the flames.

Finch-Walker says the fire has been 20 percent contained and that higher humidity and lower temperatures should help firefighting efforts.