The Slate Fire, located 23 miles northwest of Flagstaff along both the east and west sides of Highway 180, is now at 6,248 acres and 17 percent containment.
Windy and active wildfire conditions, along with burnout operations, are the main factors in the growth of the fire, which is still moving in a northeastern direction.
Crews plan to spend Friday conducting firing operations on the west side of Slate Mountain to bring the fire out to control lines. The firing operations are expected to last 24 to 48 hours, and will allow crews to hold control lines on the west side of Slate Mountain and then shift remaining resources to the east side of the fire. Crews also plan to utilize natural fuel breaks and allow the fire to burn thicker fuels.