The fire in northern California has been burning for two weeks, threatening a stretch of the Sonoma and Napa counties and destroying homes and crops.
The fire began on the slopes of the Sierra Nevada, spreading west along the ridge line and then south through the foothills of the mountains.
More than 50 firefighters from multiple agencies battled the blaze.
They had been battling fires in the area since December.
The Sonoma County Sheriff’s Office announced on Wednesday that the cause of the fire has not been determined.
The area is heavily forested, and crews have had to battle heavy rains, snow and strong winds.
“We have lost our best crews and resources,” said the sheriff, whose agency is responsible for firefighting in the Sonomas, Napa and Napo counties.
“It is going to take some time to get through this.
We have had fires in this area before.
The history is not so different from what we are going through.”
The Sonomas fire is the most destructive fire to hit the region since the deadly 2008 fire in the city of Sonoma that killed six people.
That fire, in the Santa Rosa Mountains, burned more than 600 acres.
It also destroyed an entire mountain, and killed more than 60 people.
The region was hit with the worst drought in California history, and it has been forced to cut its water supply by nearly half since May.
The wildfires have led to a shortage of water, which has forced farmers to cut back their water use.
The drought has also been the subject of much debate among politicians, as the drought has exacerbated the fire threat.
A new federal study released Wednesday estimated that nearly 50 percent of the land burned by wildfires in the U.S. in 2016 was burned by drought.