By David Schwartz
PHOENIX (Reuters) - Crews battling a major wildfire along a scenic corridor in northern Arizona made progress in battling the wind-whipped blaze on Thursday, but thousands of residents were still on alert for possible evacuations, fire officials said.
Officials said crews working overnight secured a troublesome front of the so-called Slide Fire that the day before had advanced toward 300 homes and businesses in Oak Creek Canyon, about 120 miles north of Phoenix.
The fire, which broke out on Tuesday afternoon, spread to blacken more than 7,500 acres but by Thursday night it was 5 percent contained, fire officials said.
"Today was a very good day," said Dillon Winiecki, a spokesman for the Flagstaff Fire Department. "Crews are making good progress keeping the fire in the area we want it to be."
Erratic winds kept firefighters active snuffing out a series of spot fires before they became dangerous, he said.
More than 3,000 residents in two area subdivisions have been put on a pre-evacuation notice by authorities and told they must prepare to flee their homes if the fire gets closer.
Officials estimated the blaze was more than three miles away.
Incident Commander Tony Sciacca said a stray ember could quickly spread the fire, adding that "a pre-evacuation is just what it says, be ready."
Some residents living along a two-mile (4-km) stretch near the canyon were evacuated late on Tuesday afternoon, officials said.
More than 800 firefighters were on the scene, trying to gain control of the fire that broke out in steep terrain and grew quickly, aided by strong, gusty winds.
Officials reported that weather conditions should improve during the next several days, with reduced winds, higher humidity and a chance of precipitation.
The fire, believed to have been caused by humans, broke out north of Slide Rock State Park, a popular recreation area.
No homes have been lost and there have been no injuries, officials said.
The American Red Cross has set up an emergency shelter at a middle school in nearby Flagstaff, Arizona, for those forced to flee their homes.
(Editing by Alex Dobuzinskis and Peter Galloway)