A fast-moving Arizona wildfire tripled in size on Wednesday as weather conditions are expected to worsen, further fueling the massive wind-driven blaze.

The so-called Tunnel Fire has grown to nearly 20,000 acres, up from 6,000 acres Tuesday, as it burns 14 miles north of Flagstaff. Conditions are expected to become windier Thursday and Friday with gusts up to 50 miles per hour in most of northern Arizona, according to a U.S. Forest Service statement.

YUMA BORDER WALL GAPS LEADING TO FLOOD OF ILLEGAL IMMIGRANTS: ‘WE’RE GOING TO GET THIS BACKLOG'

Smoke from the Tunnel Fire fills the sky in Doney Park, outside Flagstaff, Ariz., on Tuesday, April 19, 2022. (Cheryl L. Miller-Woody via AP)

Smoke from the Tunnel Fire fills the sky in Doney Park, outside Flagstaff, Ariz., on Tuesday, April 19, 2022. (Cheryl L. Miller-Woody via AP)

National Weather Service Meteorologist Brian Klimowski said an expected drop in humidity Thursday is "conducive to rapid wildfire growth."

At least 25 structures were burned as the fire moved through the Timberline Estates and Wupatki Trail communities, according to Coconino County officials. Thousands of people have been forced to evacuate their homes.

Coconino County Sheriff Jim Driscoll said there is no set date for when people will be able to return to their homes. 

Officials are working to provide temporary housing for people displaced by the fire, in addition to setting up an evaluation center at an area middle school.

PHOENIX PICKUP TRUCK SMASHES INTO MUSEUM, DRIVER TAKEN TO HOSPITAL WITH NON-LIFE THREATENING INJURIES

In this photo provided by the Coconino National Forest, the Tunnel Fire burns near Flagstaff, Ariz., on Tuesday, April 19, 2022. (Coconino National Forest via AP)

In this photo provided by the Coconino National Forest, the Tunnel Fire burns near Flagstaff, Ariz., on Tuesday, April 19, 2022. (Coconino National Forest via AP)

The Tunnel Fire started around 4:30 p.m. Sunday. The cause of the fire remains unknown. The National Forest Service said there were no indications, as of now, that a campfire could have sparked the blaze. 

A fire investigation team is working to determine the cause of the fire. Teams are set to conduct infrared flights Wednesday night and Thursday to identify intensity and other characteristics of the fire. 

Smoke from the Tunnel Fire fills the sky in Doney Park, outside Flagstaff, Ariz., on Tuesday, April 19, 2022. (Cheryl L. Miller-Woody via AP)

Smoke from the Tunnel Fire fills the sky in Doney Park, outside Flagstaff, Ariz., on Tuesday, April 19, 2022. (Cheryl L. Miller-Woody via AP)

CLICK HERE TO GET THE FOX NEWS APP

At least 260 firefighters are battling the blaze with the help of three bulldozers, 24 fire engines, one air attack plane and a helicopter. The U.S. Forest Service said more air assets are on order.

Officials expressed concern about the risk of flooding from the upcoming monsoon season, saying it's just another weather threat the community is facing.