Updated

FLAGSTAFF, Ariz. (AP) — Firefighters were making progress Thursday containing a wildfire that has burned more than 23 square miles of scenic northern Arizona forest.

U.S. Forest Service spokesman Willie Begay said the Schultz fire burning near Flagstaff was 40 percent contained after charring 14,800 acres, or more than 23 square miles. No major injuries have been reported and no structures have burned.

Begay said fire bosses are concerned about winds of 15 mph predicted in the fire zone Friday, with possible gusts over 25 mph. Air tankers packed with fire retardant and helicopters dropping water are on standby in case fire managers need to call them in.

Crews spent Thursday securing and building fire lines on the west, south and north sides of the fire as they prepare for whatever the wind brings. Dark smoke could be seen east of Flagstaff on Thursday afternoon.

Firefighters continued to set intentional fires to rob the main blaze of fuel and keep it from advancing on some of the area's large mountain ranges.

Managers had enough confidence in their fire lines Wednesday to let the local sheriff lift an evacuation order that forced about 1,000 homeowners and their families to flee Sunday, but he warned residents to be prepared to leave again if necessary.

U.S. 89, the main highway between Flagstaff and Page, was open Thursday, but fire information officer Larry Tunforss said the roadway could close again because of smoky conditions.

The Forest Service is offering a $2,500 reward for information that leads to the person or persons responsible for starting the fire over the weekend. Authorities said the fire was sparked by a campfire that wasn't properly extinguished in the area of Schultz Tank, Little Elden Trail and Forest Road 420.

The firefighting effort has cost taxpayers nearly $3 million.