Update at 1 p.m.:
Some 800 homes in Mariposa County are now threatened by the Carstens Fire, which was fueled by high winds and grew Monday.
No homes have been destroyed.
The fire about six miles northeast of Mariposa along Highway 140 grew from 900 acres to 1600 acres Monday and forced the evacuation of hundreds more people. It is 15 percent contained.
The mandatory evacuations are in the areas of Hites Cove, Jerseydale, Clarks Valley, Triangle Road, Scott Road, Lush Meadows and parts of East West Fall Road and Darrah Road.
An evacuation center for displaced residents has been established at Mariposa Elementary School. Their pets are being housed at the Mariposa Fairground.
More than 2,200 fire personnel are battling the blaze. No one from Modesto has been sent to assist at this point.
Investigators determined Tuesday that the fire was started by an unattended campfire.
More than 700 firefighters are battling two wildland blazes in the foothills of Madera and Mariposa counties, one of which is threatening hundreds of homes.
State fire officials say the Carstens fire, which started Sunday, has burned 1,600 acres about six miles northeast of Mariposa along Highway 140, one of the main routes into Yosemite National Park. The California Department of Forestry and Fire Protection listed the fire as just 15 percent contained Monday evening.
"The crews are working really hard and taking care of business," said Troy Cheek, a firefighter with Cal Fire who worked for 36 hours straight, from the start of the fire. "We're using everything in our arsenal to stop this fire. A lot of us live around here."
Mandatory evacuations are in place for more than 150 homes; others are under an evacuation warning.
Residents who were evacuated Sunday live in the areas of Hites Cove, Jerseydale and Scott Road.
Ed Helms was celebrating Father's Day on Sunday at his home in Hites Cove with his wife and three adult children when they were given notice to evacuate.
"We had to leave the steaks we were cooking on the barbecue to pack up and get out," he said.
He and his wife, their daughter who lives with them and a daughter who lives next door loaded family pictures, legal documents and pets into their vehicles. "Anything that couldn't be replaced," Helms said.
The family stayed with Helms' son in Mariposa.
"As we were leaving, right when we got down about a mile from our house, we looked behind us and could see the flames coming over the range," he said. "It's hard having to drive away from your home."
A search-and-rescue worker posted a notice on a tree in front of the Helms home that listed the number of people and pets that live there.
Between the Helmses and their daughters, they took six dogs, but a cat that couldn't be found in time was left behind.
Helms said the helpless feeling of leaving his home has been compounded by the lack of information about the status of the property.
He learned Monday afternoon that the fire had shifted away from his neighborhood, but he doesn't know when he and his family will be able to return.
Additional evacuations were ordered Monday night for the Lushmeadows neighborhood, east of East Westfall Road, Triangle Road to Triangle Park Drive and Darrah Road to North Valley View.
An evacuation center is open at Mariposa Elementary School to accommodate residents of some 500 homes threatened by the fire.
State fire spokesman Daniel Berlant said the fire is being driven by high winds. It started off Carstens Road, east of Highway 140 near Midpines in the Sierra National Forest.
The smaller Rolling Hills fire, meanwhile, burned about 482 acres near the Madera County city of Friant. As of 8 p.m. Monday, that fire was 90 percent contained, according to Cal Fire. Highway 41 from State Route 145 to O'Neals Road closed about 1:30 p.m. Monday and remained closed throughout the evening.
The cause of both fires is under investigation.
The San Joaquin Valley Air Pollution Control District issued a smoke warning for eastern parts of Merced, Madera, Fresno, Tulare and Kern counties.
"Our standard is, if you can see smoke and smell smoke, you are being affected," said Samir Sheikh, the air district's director of air quality analysis.
A haze of smoke was visible east of Modesto on Monday afternoon.
Smoke from fires produces fine particulate matter that can cause serious health problems including lung disease, asthma attacks and an increased risk of heart attack or stroke, according to the district.
Modesto Bee staff writer Erin Tracy can be reached at email@example.com or (209) 578-2366.