Last Updated May 21, 2014 4:19 PM EDT
OAK CREEK CANYON, Ariz. -- Hundreds of firefighters poured into Arizona on Wednesday to battle a wind-whipped wildfire burning in a rugged canyon between Sedona and Flagstaff, forcing the evacuation of resorts and campgrounds and sending choking plumes of smoke across the area.
About 200 firefighters and other personnel are already assigned to the fire, including five Hotshot crews, Coconino National Forest officials said Wednesday. An additional 15 Hotshot crews are on order, as well as 10 other firefighting crews and dozens of fire engines, officials said. A top-level fire management team was to take over command Wednesday afternoon.
The fire had blackened at least 850 acres on the western slope of the canyon by Wednesday morning, U.S. Forest Service spokesman Brady Smith told CBS Phoenix affiliate KPHO-TV.
Coconino National Forest officials announced on Twitter that the wildfire was expected to grow to up to 2,000 acres by Wednesday night.
There are no reports so far of injuries or structures burned. The exact cause of the fire is not yet known, but authorities believe it was human-caused.
The fire broke out at the start of the tourist season and closed a main road between Sedona and Flagstaff - two cities that attract large amounts of visitors in summer months as people flock to the mountains for camping and hiking. The fire is burning near Slide Rock State Park, a popular recreation area because of its natural rock water slides.
The fire forced the evacuations of 100 threatened businesses and homes in a 2-mile stretch north of the state park, and 15 people stayed at a shelter in Flagstaff.
The canyon fire comes less than a year after a blaze in nearby Prescott killed 19 firefighters who were part of a Hotshot crew.
As the fire moved up the canyon's steep walls, it sent up large amounts of smoke and ash and created hazy conditions in Flagstaff, about 10 miles from the blaze.
The blaze presented several challenges for firefighters, including steep terrain, thick pine forest, gusting winds and a drought that has left parts of Arizona tinder-dry, said Bill Morse, a Flagstaff Fire Department captain and a spokesman for firefighting managers. He also said the terrain makes it difficult for firefighters to stay in contact with each other on their radios.
But Morse said calming fire conditions in Southern California have freed up extra crews to fight the Arizona fire.
"Fortunately the fires in San Diego have calmed down enough for the resources to be released here," Morse said.
The evacuees included Nathan and Mickella Westerfield, young honeymooners from Phoenix who arrived at a campground in the canyon Tuesday afternoon. They were headed into Sedona for dinner when they passed the fire, which was burning shrubs and trees in a small valley visible from the highway.
As other passers-by stopped to take pictures of the fire, a firefighter told the couple they couldn't return to their campground to retrieve their newly purchased camping gear and other belongings, Nathan Westerfield said.
"He told us, 'no, we're evacuating,'" he said. "We literally have the clothes on our backs."
Red Cross spokeswoman Trudy Thompson Rice said most of the 15 people who stayed Tuesday night at the shelter at a Flagstaff school were campers. The Westerfields were among those who spent the night at the shelter.
"We had a lot more than that - maybe 30 - come in to register and let us know where they were," she said Wednesday.
A separate wildfire in the state burned 200 acres and closed Interstate 17 near Cordes Junction in both directions for more than four hours late Tuesday. The interstate, which is the main traffic route between the Phoenix area and northern Arizona, reopened Tuesday evening.