The so-called Tunnel Fire was burning about 14 miles north of Flagstaff. County officials said nearly 800 households and over 1,000 animals were evacuated from the area that is home to more than 2,000 people.
"This was a very difficult evacuation procedure," said Coconino County Sheriff Jim Driscoll. "The rapid movement and progression of this fire made the evacuation much more difficult and complicated than we've had in the past."
Driscoll said his office did receive calls of people trapped in their homes, but authorities were unable to reach their locations due to the fire. He said it remains unclear if those people survived.
At least two dozen structures were destroyed by the fire and hundreds more are threatened as the wildfire moves rapidly in a northeasterly direction, officials said.
"The fire was moving so fast that many of those officers were in harm's way themselves," Driscoll said. "I'm very proud of the fact that we were able to get this evacuation done despite the rapid progression of the fire."
The Tunnel Fire started around 4:30 Sunday afternoon. A fire investigation team is expected Wednesday to help identify the cause of the fire and study how it has progressed.
Coconino County officials declared a state of emergency and urged people to pay close attention to evacuation orders.
The Federal Emergency Management Agency's (FEMA) regional administrator authorized the use of federal funds on April 19 to assist the state of Arizona in combating the fire.