‘A lot of dead fuel’ challenges firefighters as Oak Fire grows to more than 14,000 acres

The Oak Fire burning west of Yosemite National Park topped 14,000 acres by early Sunday morning, leaving thousands of people evacuated as firefighters battled California’s largest and most explosive wildfire of 2022.

The blaze tore through 14,281 acres across Mariposa County and it remained 0% contained as of shortly after 7 a.m. Sunday, according to Cal Fire. More than 2,600 structures are threatened, leaving about a third of the county’s residents under evacuation as flames barreled through tinder-dry landscape awakened by years of severe drought.

More hot, dry weather is expected to further challenge firefighters Sunday. The fire pushed south and southeast throughout Saturday night — a path it’s expected to continue to take on Sunday as light winds blow in from the northwest, said Hector Vasquez, a Cal Fire spokesman. The greatest concern is for the small communities of Jerseydale to the northeast, Darrah to the east and Bootjack to the south, he said.

“This whole area already has a pretty heavy fuel load — anywhere it pushes, there’s a lot of fuel to be consumed,” Vasquez said.

Temperatures are expected to climb to the high 80s or low 90s and humidity levels are forecast to hover in the teens throughout much of the day, said Jeffrey Barlow, senior meteorologist with the National Weather Service.

The winds are expected to remain relatively calm, he said, but the problem is that the forest is already dry and ready to burn.

“The real problem here is now with meteorological conditions, it’s with the amount of fuel from the pine beetle kill,” said Barlow, adding that a severe wind event earlier this year knocked down many dead or weakened trees. “There’s a lot of dead fuel and that’s what’s allowing this explosive type of fire behavior.”

Slightly more than 2,000 people are assigned to fight the blaze, along with 225 fire engines and 58 dozers to cut fire lines ahead of the flames, according to Cal Fire. Seventeen helicopters have been tasked with dropping water on the blaze as well.

The fire ignited Friday afternoon near State Route 140 and Carstens Road in the largely rural Midpines region of Mariposa County. But fueled by drought-stricken trees, it exploded on Saturday into a monster — sending a pyrocumulous cloud soaring 20,000 feet into the sky as it pushed further in the Sierra National Forest.

At least 10 structures have already burned and five others have been damaged, Cal Fire reported. The flames remain a few miles northeast of the historic town of Mariposa — a town dating to California’s Gold Rush days, with buildings built in the 1850s.

Gov. Gavin Newsom on Saturday declared a state of emergency in Mariposa County and announced that the state had received a federal Fire Management Assistance Grant through the Federal Emergency Management Agency to help offset the cost of fighting the blaze.

Forty-two people stayed Saturday night at an evacuation center established at Mariposa Elementary School by the American Red Cross of the Central Valley, said Taylor Poisall, a spokeswoman for the organization. About 30 people stayed there on Friday night, along with many dogs, cats, cockatiels, turtles and a new littler of kittens.

Many of those evacuees hailed from Flush Meadows and Bootjack and other small communities across Mariposa County. Some of them have since been told that their houses have burned, Poisall said.

“A lot them are neighbors and they take care of each other,” Poisall said. “And it’s really nice to see  neighbors supporting neighbors.”

Updated smoke forecast for the #OakFire suggests smoke will impact northeastern CA and western NV today. For real-time air quality information, visit https://t.co/bs3mf3Mh7p #cawx #nvwx pic.twitter.com/ItJkL9ZfI5

— NWS Reno (@NWSReno) July 24, 2022

Smoke from the blaze choked much of the surrounding Sierra Nevada on Sunday morning. Hazardous air quality levels were reported along Highway 50 from Pollock Pines to South Lake Tahoe. And unhealthy conditions were seen from Donner Pass south to Mariposa.

More smoke is expected to drift over northeastern California and western Nevada on Sunday, saturating the air with harmful particulates and potentially causing difficulty breathing for people in the area.

A town hall meeting for people impacted by the blaze is scheduled for 7 p.m. Sunday in the gymnasium of Mariposa County High School, 5074 Old Hwy N.

Air in the Bay Area is expected to remain mostly clear for the next 24 hours thanks to the marine layer’s moisture content that is keeping the smoke out, said NWS meteorologist Brayden Murdock.

As the moisture content decreases on Monday, small traces of smoke may reach the far eastern and northern regions of the Bay Area, including the parts of Contra Costa, Napa and Solano counties. The Bay Area Air Quality Management District issued an air advisory for Monday, noting that the smell of smoke may be apparent at higher elevations.