An Arizona wildfire ballooned from 200 acres to 1,000 acres overnight, officials said Monday.
Firefighters working to contain the fire in a national forest about a mile north of Flagstaff planned to conduct controlled burning to create a perimeter around the blaze Sunday night, but couldn't because the flames were "very active overnight," according to a statement from the Coconino National Forest.
Crews "took indirect suppression tactics where they could," the statement said.
The blaze, dubbed the Museum Fire, was first reported by the national forest at about noon Sunday. At that time, the fire was just 5 acres, but growing, officials said. Less than 24 hours later, the fire was burning about 1,000 acres.
Flagstaff residents were warned Sunday night that heavy smoke would hamper air quality. Trails and campgrounds within the forest were closed, and residents in nearby neighborhoods were told to be prepared to evacuate if necessary.
A shelter was opened at a Flagstaff middle school at the request of local emergency managers, according to the Red Cross.
Officials said smoke would be the most intense in low lying areas of Flagstaff during cooler hours Monday, and lift as the day warms up.
About 200 firefighters have responded to the Museum Fire, along with five helicopters and more than a dozen aircraft, according to national forest officials. Three Hotshot crews are on the scene, and 10 more have been requested.
Gov. Doug Ducey said in a statement Sunday night that his office was in contact with emergency responders. "My thoughts and prayers are with the firefighters and first responders working to protect Arizonans, their pets and their property," the statement said.
The cause of the fire is under investigation. The mercury hit the 90s in Flagstaff on Sunday, with a 1 percent chance of precipitation, according to the National Weather Service. The high temperature Monday is expected to reach 89 degrees.