UPDATED 9:06 p.m.
The U.S. Forest Service says about 1,500 firefighters and support personnel are now on the fire.
UPDATED 4:36 p.m.
The Ferguson Fire has grown to more than 9,000 acres with 2 percent containment since it started late Friday.
One of the main roads into Yosemite National Park, Highway 140, is closed about 10 miles north of the town of Mariposa and evacuation orders and advisories are in place.
So far, the fire has burned to the southeast, away from Highway 140.
The U.S. Forest Service says most of the firefight during the night and early morning has been undertaken by crews on the ground. Their efforts have been hampered by rocky areas that are inaccessible by vehicle. The air attack has been limited by thick smoke that hinders visibility.
"In the early hours of the day, the smoke is not allowing the air tankers to get up and to do their job,” said Alex Olow with the USFS. “With that said, in the mid-afternoon [sic] the smoke has lifted quite a bit. So, the air attack and the air tankers should be able to get in there. That's kind of been the story for the last three days."
More than 600 people are fighting the fire, with more on the way.
Cal Fire, the USFS and the Sacramento County Sheriff’s Department have created a joint command. The designation frees up more resources to fight the fire.
Weather conditions include 100 degree heat and dry fuels.
More than 100 structures are threatened to the east and south of the fire, but none have burned so far. There have been mandatory evacuations for four areas of Mariposa County: Clearing House, Mariposa Pines, Cedar Lodge/Savage’s Trading Post and Sweetwater Ridge.
Olow said firefighters on the western flank have retreated to Sweetwater Ridge.
"To the west, there's an area where we've pulled back somewhat, only because of steep terrain and firefighter safety,” Olow said.
Evacuation advisories were extended to 15 miles southeast from the source of the fire, Savage’s Trading Post on Highway 140.
A Red Cross evacuation center has been established at the New Life Christian Center on Cole Road in Mariposa. So far, 25 people have been to the shelter.
On Friday night, a bulldozer accident claimed the life of firefighter and Mariposa native Braden Varney. Cal Fire says he was clearing fire lines when the accident happened. The incident is under investigation.
No date for memorial services has been set.
No cause of the fire has been released.