Crews are building the last few miles of fire lines to contain the blaze. They are expected to face warm temperatures and gusty winds.
Authorities believe the wildfire was sparked by a state-controlled burn that reignited on Monday in strong winds. Residents of about 180 homes have been evacuated.
Two people were found dead in the fire zone, and one woman remains missing.
Some 400 firefighters from Colorado, Idaho, Nevada and Utah have been sent to assist, and at least four aircraft are also involved in the firefighting effort.
The Associated Press contributed to this report.