A wildfire that erupted Friday near Yosemite National Park in Mariposa County has torched more than 9,500 acres, triggered widespread evacuations and on Saturday threatened 2,000 structures.
The Oak Fire is the largest and fastest expanding California wildfire so far this year and Cal Fire on Saturday afternoon reported zero containment.
“Explosive fire behavior is challenging firefighters,” the department said in a mid-afternoon incident report.
The blaze broke out in the vicinity of State Route 140 and Carstens Road — a heavily forested area in the largely rural Midpines region of Mariposa County — and then roared into the wildlands beyond the point of origin, prompting evacuations across the county, Cal Fire said.
As of Saturday afternoon, the fire had destroyed 10 residential and commercial structures and damaged five more. Over 6,000 residents — more than a third of Mariposa County’s total population — were ordered to evacuate, a spokesman for the Sierra National Forest told the Associated Press.
The fast-growing blaze prompted Caltrans to order numerous road closures, including a shutdown of Highway 140 between Carstens Road and Allred Road, which blocked one of the main routes into Yosemite National Park.
Large columns of smoke hung in the air over the Sierra Foothills, visible as far as nearly 50 miles away in the Merced area on Friday evening. State fire officials were investigating what caused the wildfire to ignite.
“Fire activity is extreme with frequent runs, spot fires and group torching,” Cal Fire stated in a post on its incident site. “Emergency personnel are working to safely evacuate people and are actively engaged in protecting structures. Explosive fire behavior is challenging firefighters.”
Lending to the fire’s rapid expansion on Friday is the nature of the Midpines region’s terrain — steep and rugged, with a heavy fuel load due to a lack of recent fire history in the area, said Cal Fire spokeswoman Natasha Fouts.
“There are a lot of tree mortalities in the area that produce more bark fuel,” Fouts said, “and if the winds torque the trees, that produces more embers, which could create spot fires that our firefighters have to deal with.”
Fortunately, the region is expected to see cooler temperatures on Saturday, accompanied by calmer winds that could slow the blaze’s spread: “We’re hoping all that will work in our favor,” she said.
Yosemite National Park saw its own blaze earlier this month when the Washburn Fire broke out in the area of Mariposa Grove, burning 4,800 acres with 79% containment by fire crews as of Friday and no homes destroyed.
By comparison, the Oak Fire is significantly faster-moving — official accounts show it had quickly gained momentum in its early stages.
The Mariposa County Sheriff’s Office ordered mandatory evacuations in an area that included the Midpines community. The evacuations have reached beyond the community of Jerseydale in Mariposa County.
The ArcGIS mapping and analytics service showed that the area of mandatory evacuations has grown rapidly.
Just one hour after Cal Fire had estimated the blaze’s size at 60 acres, the wildfire had swiftly expanded to a size that exceeded 600 acres. An hour after that it had more than doubled in size to 1,300 acres. The fire’s size continued to expand dramatically during the night.
That deer fleeing the #oakfire last nite? It was following the lead of a wild turkey, or a peacock. I can't tell. pic.twitter.com/eMfwW8gDQ5
— Karl Mondon (@karlmondon) July 23, 2022
An evacuation center was set up at Mariposa Elementary School, 5044 Jones St. in Mariposa. The spread of the fire was so rapid that an initial evacuation center had to be abandoned due to safety concerns.
Taylor Poisall, an American Red Cross spokeswoman and volunteer at the Mariposa Elementary shelter, said at least 70 people had arrived since Friday, filling the school’s cafeteria while dogs, cats, birds and turtles sheltered in vacant classrooms.
“This is a really resilient area, because they unfortunately have to evacuate often,” Poisall said, noting that the Washburn and Agua fires had similarly prompted evacuations, though neither to the scale of the Oak Fire.
“People were concerned about their homes and pets, since lots of people have livestock out here, but most people have emergency plans, and a lot of them are staying with neighbors in unaffected areas,” she added.
Some of Mariposa County’s popular rural wineries and farms fall in the area’s evacuation zones. But the county’s historic downtown — filled with local restaurants and hotels, with the elementary school nearby — remains safely to the east.
Here is a list of road closures as of Saturday morning:
Carstens Road, Triangle Rd from Hwy 140 to Hwy 49 south, Buckingham Mt. Rd, Plumbar Creek Rd, Jerseydale Rd and all side roads, Hwy 140 from Allred Rd to Ponderosa Way, Darrah Rd, Silva Rd from Triangle to Cole Rd, Cole Rd, McNally Rd, Boyer Rd and all side roads, Brooks Rd, Woodland Dr, Carelton Rd to Morningstar Rd and Morningstar Rd.
Evacuation orders apply to these roads:
Carstens Rd, Buckingham Mt. Rd, Plumbar Creek Rd, Triangle Rd from Hwy 140 to Highway 49 south, Carter Rd, Darrah Rd from Triangle to Valley View and all sides of the road, Silva Rd from Triangle to Van Ness Rd, Boyer Rd from Hwy 49 south and all side roads, Darrah Rd from the stop light to Triangle Rd, Triangle Rd from Hwy 49 south to Westfall Road and all side roads including Triangle Park, Tip Top Rd, Wass Rd, Westfall from Triangle to Oliver Creek. Silva Rd from Cole to Triangle and all side roads, Gingers Trish Rd, Cole Rd to Darrah Rd including all side roads, Darrah Rd from Hwy 49s to Triangle Rd including all side roads, McNally Rd. Hwy 49 south from Darrah Rd to Triangle east side of the road (Bootjack Market Side), Woodland Dr, Brooks Rd, Indian Rock Ln, Morningstar Rd from Carleton to Allred and all side roads, Carleton Rd. from Triangle to Morningstar.
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Check back for updates. Staff photographer Karl Mondon, staff writer Paul Rogers and the Associated Press contributed to this report.
- California wildfire season survival guide: How to prepare for fire and smoke
