Oak Fire update: Wildfire near Yosemite has destroyed 25 homes, scorched 18,000 acres

The quick-moving Oak Fire has destroyed 25 homes, Cal Fire said Tuesday morning, and another 16 out buildings.

The blaze has burned more than 18,000 acres since beginning near Highway 140 and Carstens Road on Friday in Mariposa County, Cal Fire said.

The cause of the fire is still under investigation as crews have contained about 26% of the fire.

“Smoke from the fire is producing poor visibility to the north of the fire during the day and across the fire at night,” Cal Fire’s update said.

Still, more than 1,400 other structures are threatened by the Oak Fire.

Nearly 3,000 firefighters are working in the area, which includes 302 engines and two dozen helicopters. There are also 82 bulldozers and 68 water tenders, Cal Fire said.

Oak Fire air quality

Smoke from the fire near Midpines may make its way down to the central San Joaquin Valley, according to the San Joaquin Valley Air Pollution Control District.

The district says if you can smell smoke or see ash, those are clear indications the air quality is being affected.

The Oak Fire continues to burn to the north, as well as down a slope in rugged terrain east into Devil’s Gulch, east of Jerseydale.

So far no injuries or fatalities have been reported, Cal Fire said.

Hot spots revealed by infrared

New infrared video taken by aircraft flying over the Oak Fire near Mariposa on Monday afternoon shows significant hot spots where the wildfire is burning with the most ferocity.

A reconnaissance flight by the state Office of Emergency Services for its Fire Integrated Real-time Intelligence System, or FIRIS, shortly after 12:30 p.m. indicates significant heat activity at the northern and northeastern edges of the fire’s perimeter.

The videos underscore what firefighters have said about the speed at which the Oak Fire has grown since it started Friday. By Saturday morning, it had blistered more than 6,500 acres, quickly becoming the largest wildfire this year in California.

The fire has continued to expand, now three times the size of the next largest fire, a May incident in Riverside County. “The fire fight continues in hot, dry conditions and steep, rugged terrain,” Cal Fire reported Monday.

With afternoon high temperatures in the high 80s to low 90s, and breezes blowing at 13 to 15 mph, “we still have ripe conditions for the fire to take off and create more havoc,” Joe Amador, a fire information officer on the Oak Fire, told The Fresno Bee on Monday afternoon.

Nighttime conditions have also been dry, with low humidity creating a situation in which the fire continues to burn. Amador said fire crews were expecting relief overnight Monday as some monsoon moisture moved in, helping to increase the humidity and slowing the fire’s nighttime activity.

The Oak Fire quickly eclipsed the Washburn Fire, which is still burning about 10 miles to the east in Yosemite National Park and the adjacent Sierra National Forest. The Washburn Fire, which was ignited July 7 in Yosemite National Park’s Mariposa Grove, is at 4,875 acres and is about 87% contained, according to the National Interagency Fire Center and the National Park Service.

Another wildfire in the mountain area, the Agua Fire just west of Mariposa, began July 18 and is 100% contained by firefighters, Cal Fire reported.

Swaths of mountain territory on all sides of the fire remain under mandatory evacuation orders, and evacuation warnings extend even further – as far north as Briceburg, east to Chowchilla Mountain, west toward Bullion Mountain and south to the Madera County line.