PHOENIX -- A 12-acre wildfire that broke out Monday afternoon in northern Arizona's scenic Oak Creek Canyon just north of a blaze that charred 31 square miles last month was 25 percent contained by nightfall.
The so-called Junipine Fire started about 3:30 p.m. Monday and was believed to have been sparked by a downed power line, authorities said.
Pushed by wind gusts, authorities say the fire was at about 20 acres and burning north toward the charred remains of the human-caused Slide Fire, which started May 20 near Slide Rock State Park in the scenic canyon between Sedona and Flagstaff.
"It looks like it's moving north," Sedona Fire Department spokesman Gary Johnson said. "When it hits that black area, it's going to lay down or not burn at all."
Coconino National Forest officials said crews were cautiously optimistic of having the fire fully contained by Tuesday.
No structures were immediately threatened. But the Junipine Lodge and about a dozen nearby homes were under a mandatory evacuation order as a precaution, affecting about 40 people, Coconino County sheriff's officials said.
They said Oak Creek Canyon residents north of Junipine to the bottom of the switchbacks were given a pre-evacuation notification.
A shelter was being set up for evacuees at a middle school in Flagstaff.
Highway 89A from the northern Sedona city limits to Slide Rock State Park was partially closed by the state Department of Transportation.
Authorities said about 70 firefighters were battling the wildfire along with four engines and an air attack.
KTAR'S Jim Cross and The Associated Press contributed to this report.