A rapidly spreading wildfire near Lake Berryessa in Napa County, California, has chewed up at least 4,000 acres, and is now threatening about 150 structures, California Department of Forestry and Fire Protection (Cal Fire) said late Wednesday. Authorities ordered mandatory evacuations in at least two communities in the area.

Firefighters were able to contain just 5 percent of the fire, which started Wednesday afternoon, according to Cal Fire’s website. Although it was believed that a vehicle accident led to the massive fire, authorities are investigating the cause.

“The fire has remained consist, in traveling, at a rapid rate of spread. The terrain is brush covered, rugged and steep, with difficult access. Winds are erratic,” the website stated.

Authorities have evacuated hikers in Cold Canyon Area along with residents in nearby areas of Lake Berryessa. However, it remained unclear how many people were told to evacuate.

No injuries have been reported and no structures have been damaged in the fire so far.

Officials have closed Highway 128 in the area as the firefighters control the blaze. According to Cal Fire, 300 firefighters and four helicopters were deployed to battle the wildfire, Reuters reported.

California is struggling with drought for the fourth straight year. “The drought has absolutely led to drier-than-normal conditions,” said Cal Fire spokesman Dan Berlant, according to SFGate, a local news network. “It doesn’t take much for a fire to start.”

Red Cross has opened an evacuation center at the Winters Community Center, Yolo County. A large animal evacuation center is also opened in the area.