FLAGSTAFF, Ariz. -- Crews fighting a wildfire in a northern Arizona canyon focused Monday on building containment lines along the last unprotected stretch of the blaze.
Firefighters will build 3 miles of protection lines on the southern end of the Slide Fire after having completed much of their work on the blaze's key northern and western flanks.
The human-caused fire has been burning since Tuesday around Oak Creek Canyon, a scenic recreation area along the highway between Sedona and Flagstaff that would normally be crowded with tourists Memorial Day weekend. Slide Rock State Park, one of the most-visited tourist spots in Arizona, has been closed.
No homes have been destroyed.
The fire covered more than 25 square miles and was 25 percent contained by Monday morning. It had grown more than 3 square miles since the latest report on its size.
The goals for fire managers are to protect the 300 structures threatened in Oak Creek Canyon, keep the fire from pushing into the communities of two subdivisions to the east and minimize the potential for flooding.
Though warmer temperatures and drier air are expected Monday, lower temperatures and higher humidity made the fire less intense over the last few days.
"It was perfect timing," said fire information officer Manny Cordova. "It allowed us to make good progress."
Authorities lifted a pre-evacuation warning Monday for 3,200 people living in the Forest Highlands and Kachina Village subdivisions. Mandatory evacuations will likely remain in place in Oak Creek Canyon from Slide Rock State Park to Sterling Springs Hatchery.
Crews completed their efforts to protect a power line that supplies electricity to Flagstaff.
Officials say it has cost $3.5 million so far to fight the fire. The cause of the fire remains under investigation.