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WAWONA, Calif. — A fast-moving brush fire near Yosemite National Park exploded in size Saturday into one of California's largest wildfires of the year, prompting evacuation orders for thousands of people and shutting off power to more than 2,000 homes and businesses.

The Oak Fire started Friday afternoon southwest of the park near the town of Midpines in Mariposa County and by Saturday had grown to nearly 19 square miles (48 square kilometers), according to the California Department of Forestry and Fire Protection, or Cal Fire. It erupted as firefighters made progress against an earlier blaze that burned to the edge of a grove of giant sequoias in the southernmost part of Yosemite park. Acreage is at about 11,900.

Evacuation orders were put in effect Saturday for over 6,000 people living across a several-mile span in the sparsely populated, rural area, said Daniel Patterson, a spokesman for the Sierra National Forest.

Gov. Gavin Newsom proclaimed a state of emergency for Mariposa County on Saturday due to the effects of the Oak Fire.

More than 400 firefighters were battling the blaze, along with helicopters, other aircraft and bulldozers, facing tough conditions that included hot weather, low humidity and bone-dry vegetation caused by the worst drought in decades, Patterson said.

“Explosive fire behavior is challenging firefighters,” Cal Fire said in a statement Saturday that described the Oak Fire's activity as “extreme with frequent runs, spot fires and group torching.”

By Saturday morning, the fire had destroyed 10 residential and commercial structures, damaged five others and was threatening 2,000 more structures, Cal Fire said. The blaze prompted numerous road closures, including a shutdown of Highway 140 between Carstens Road and Allred Road — blocking one of the main routes into Yosemite.

California has experienced increasingly larger and deadlier wildfires in recent years as climate change has made the West much warmer and drier over the past 30 years. Scientists have said weather will continue to be more extreme and wildfires more frequent, destructive and unpredictable.

“The fire is moving quickly. This fire was throwing embers out in front of itself for up to 2 miles yesterday,” Patterson said. “These are exceptional fire conditions." The cause of the fire was under investigation.

Pacific Gas & Electric said on its website that more than 2,600 homes and businesses in the area had lost power as of Friday afternoon and there was no indication when it would be restored. “PG&E is unable to access the affected equipment," the utility said.

A shoeless older man attempting to flee the blaze on Friday crashed his sedan into a ditch in a closed area and was helped by firefighters. He was safely driven from the area and did not appear to suffer any injuries. Several other residents stayed in their homes Friday night as the fire burned nearby.

Fire crews from the Sacramento area have already hit the road to help fight the blaze. 

The Cosumnes Fire Department, along with Sacramento Metro Fire, San Joaquin crews are on scene.

"We worked together with our cooperating agencies so Metro Fire will send out one type 3 apparatus and that is a pump and roll capable engine so that means it can roll and spray water at the same time and those are the apparatus we use on grass fire or vegetation fires in that urban interface," Capt. Parker Wilbourn with Sacramento Metro Fire. "We are also in the process of sending out our type 1 apparatus. Those are larger and have about 700 gallons of water in the tank, and they're more in a position for structural firefighting." 

Cosumnes Fire and Metro Fire are deploying crews tonight to the Oak Fire. These two OES wildland engine crews will join with others from the region to assist with this new fire. pic.twitter.com/ooQcL13eVo

Meanwhile, firefighters have made significant progress against a wildfire that began in Yosemite National Park and burned into the Sierra National Forest.

The Washburn Fire was 79% contained Friday after burning about 7.5 square miles (19.4 square kilometers) of forest. It was one of the largest fires of the year in California, along with the Lost Lake Fire in Riverside County that was fully contained in June at 9 square miles (23 square kilometers)

The fire broke out July 7 and forced the closure of the southern entrance to Yosemite and evacuation of the community of Wawona as it burned on the edge of Mariposa Grove, home to hundreds of giant sequoias, the world's largest trees by volume.

Wawona Road is tentatively set to reopen on Saturday, according to the park website.

#OakFire new shelter location: An evacuation shelter is open at Mariposa Elementary School (5044 Jones Street, Mariposa, CA 95338) for evacuees affected by the Oak Fire in Mariposa. Red Cross volunteers will provide safe shelter, water, meals and additional resources to evacuees. pic.twitter.com/O4zTDVwajw

Small Animals- Mariposa County SPCA 5599 Hwy 49 North, Mariposa (full) Small Animals-Mariposa Elementary School 5044 Jones St. Mariposa (6th and Jones) Large Animals – Maiposa County Fairgrounds 5007 Fairgrounds Rd. Mariposa

An evacuation map for Mariposa County is available below.

Mariposa County Elementary 5044 Jones St. Mariposa

This map from the National Interagency Fire Center shows fire activity (this may take a few seconds to load):

Aerial video provided by ABC7.

According to Cal Fire, the 2021 fire season started earlier than previous years, but also ended earlier, as well. January 2021 saw just under 1,200 acres burned from nearly 300 wildfires. Fires picked up in the summer when the Dixie Fire burned in five Northern California counties — Butte, Plumas, Shasta, Lassen and Tehama. The Dixie Fire started on July 13 and wasn't contained until Oct. 25, burning nearly 1 million acres. It has since become the second-largest wildfire in state history and the largest non-complex fire.

Overall, 2.5 million acres were burned in 2021 from 8,835 wildfires. Over 3,600 structures were destroyed and 3 people were killed. 

If you live in a wildfire-prone zone, Cal Fire suggests creating a defensible space around your home. Defensible space is an area around a building in which vegetation and other debris are completely cleared. At least 100 feet is recommended.

WATCH: What you need to know to prepare, stay safe for wildfires

The Department of Homeland Security suggests assembling an emergency kit that has important documents, N95 respirator masks, and supplies to grab with you if you’re forced to leave at a moment’s notice. The agency also suggests signing up for local warning system notifications and knowing your community’s evacuation plans best to prepare yourself and your family in cases of wildfires.

Some counties use Nixle alerts to update residents on severe weather, wildfires, and other news. To sign up, visit www.nixle.com or text your zip code to 888777 to start receiving alerts. 

Read more: Are you wildfire ready? Here's what to do to prepare for fire season.

PG&E customers can also subscribe to alerts via text, email, or phone call. If you're a PG&E customer, visit the Profile & Alerts section of your account to register.

What questions do you have about the latest wildfires? If you're impacted by the wildfires, what would you like to know? Text the ABC10 team at (91) 321-3310.

Watch More from ABC10: Saving Mariposa Grove Redwood Sequoia trees amid Yosemite wildfire

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