A massive wildfire in Mariposa County nearly doubled in size overnight as flames destroyed structures, threatened power to Yosemite National Park and forced 4,000 people to flee their homes.

The fast-growing Detwiler fire, which is burning west of Yosemite, exploded from 25,000 acres to 45,724 acres, the California Department of Forestry and Fire Protection said Wednesday.

On Tuesday, Gov. Jerry Brown declared a state of emergency after the fire forced thousands to evacuate and damaged power, water and communication infrastructure.

The governor’s order sends additional equipment and fire crews to Mariposa County to help fight the blaze, which is only 7% contained. The declaration also accelerates emergency aid to those affected by the fire.

Incredible video from inside the #DetwilerFire. Thanks to @lompoc_firefighters for sharing this video and thanks to all the firefighters doing all they can to keep us safe! Stay with ABC30 and ABC30.com for the latest info.

A post shared by ABC30 (@abc30_actionnews) on Jul 18, 2017 at 5:18pm PDT

As the blaze spread rapidly across thousands of acres Tuesday, the Mariposa County Sheriff’s Office issued evacuation orders to residents in the town of Mariposa, east of Merced.

Nearby highways and roads were closed as more than 2,200 firefighters tackled flames and faced “extreme and aggressive fire behavior,” Cal Fire said.

Embers from the blaze sparked spot fires, and entire trees were engulfed in flames, Cal Fire said.

The blaze, which started Sunday east of Lake McClure, has destroyed eight structures, damaged another and is threatening an additional 1,500.

The communities of Hunters Valley, Bear Valley, Catheys Valley, Mormon Bar, the town of Mariposa, Mount Bullion, the Yaqui Gulch/Agua Fria areas and Hornitos continue to be threatened, Cal Fire said. “The fire encroaches on culturally and historically sensitive areas,” it said.

To the south of the fire, flames threatened power lines that supply Yosemite, Cal Fire said.

Smoke from the #DetwilerFire impacting @YosemiteNPS as seen from the @YoseConservancy webcam #CAFire pic.twitter.com/YwmgfZHRKN

— NWS Hanford (@NWSHanford) July 18, 2017

Smoke from the fire could be seen from a weather satellite, according to the National Weather Service.

Along with dry, breezy and warm conditions that are dominating Central California this week, forecasters say, firefighters must also contend with overgrown vegetation.

“It is the fuels that are extremely flammable right now due to heavy rains this winter with widespread growth and then extended heat waves this summer which has created a powder keg for fast-burning fuels,” the weather service said in a statement. “Even terrain-driven winds can become stronger depending on fire behavior and fuels.”

According the fire’s incident management team, the fire is burning in an area where there are many dead trees killed by bark beetle and the drought.