Hundreds of California firefighters are battling a fast-moving fire that broke out Wednesday and has grown to more than 14,000 acres, prompting evacuations.

The mountain fire started Wednesday morning in Ventura County, near the city of Camarillo.

As of Thursday morning, the area has expanded to 14,187 hectares and is currently 0% contained. According to the Ventura County Fire Department, at least 800 firefighters are working to bring the blaze under control, using both ground resources and helicopters.

Local authorities said on Wednesday that more than 14,000 people had to evacuate. Evacuation orders remain in effect on Thursday.

The National Weather Service has issued a red flag warning for parts of Southwest California, indicating critical fire conditions are present or expected to occur soon.

On Wednesday, the National Weather Service’s Los Angeles office updated its red flag with the rare “extremely hazardous situation” label.

The red flag warning will remain in effect in most areas through much of Thursday and will extend into Friday morning for the same regions, including the inland, coastal slopes of San Bernardino County and the mountain areas of San Diego and Riverside County.

Warnings of high winds and dense smoke are in effect for certain regions on Thursday.

According to weather officials and local authorities, the fire started when strong Santa Ana winds came into contact with very dry air.

Weather experts say a combination of high winds, low relative humidity and warm temperatures could contribute to extreme fire behavior.

Wind gusts in some areas reached 85 mph (187 km/h) on Wednesday and humidity in some areas was as low as 8%.

On Thursday morning, the National Weather Service reported relative humidity was just 10%, with wind gusts of 60 mph in some areas.

Winds are expected to diminish later Thursday, but critical fire conditions remain until then.

“Any developing fires are likely to spread rapidly,” the National Weather Service said Thursday morning.

Ventura County Fire Department officials said Wednesday afternoon that they were aware of numerous structures damaged or destroyed by the fire, but that a more detailed assessment of the damage would be conducted once it was safe to do so.

The fire has already destroyed dozens of homes, according to the Associated Press, and fire officials also reported that at least two people have been taken to the hospital for possible smoke inhalation.

“Our firefighters are being nothing short of heroic right now,” Ventura County Fire Department Captain Trevor Johnson said Wednesday.

Due to the high fire danger, Southern California Edison temporarily turned off power to several thousand customers as part of its public safety power shutoff plan to prevent the electrical system from becoming a source of ignition.

Similarly, the Pacific Gas and Electric Company has shut off power to thousands of accounts across the state in an effort to limit the risk of ignitions.

About 3,000 customers were without power in Ventura County and just over 500 in Los Angeles County as of Thursday morning, according to poweroutage.us.

Ventura County Schools also announced that all area schools would be closed on Thursday and Friday.

California Governor Gavin Newsom announced Wednesday that the state has received federal assistance from the Federal Emergency Management Agency to help ensure the availability of critical resources for Ventura County.

“This is a dangerous fire that is spreading quickly and threatening lives,” Newsom said. “State resources have been mobilized to protect communities, and this federal support from the Biden-Harris Administration will give state and local firefighters the tools they need to save lives and property as they continue to battle this aggressive fire. ”

The Mountain Fire isn’t the only fire to break out in Southern California this week.

The widespread fire broke out in the Malibu neighborhood of Los Angeles County on Wednesday, according to local officials. As of Wednesday evening, it had grown to 20 hectares and was 15% contained, with progress halted.

According to the California Department of Forestry and Fire Protection, wildfires have burned more than 1,015,000 acres (410,756 hectares) across California this year, compared to 332,822 acres (134,688 hectares) at this time last year.

County officials have scheduled their next press conference for 10 a.m. local time (1 p.m. ET).