Firefighters are facing "extreme and aggressive fire behavior" with solid walls of flame and sparks from the main blaze setting spot fires in grasslands, the California Department of Forestry and Fire Protection (Cal Fire) said.
According to the California Department of Forestry and Fire Protection fire had scorched 101 square kilometers in Yosemite National Park.The blaze burning since Sunday was making its way to the hills on the edge of Mariposa.
The Detwiler Fire, named for one of the roads in the area, is one of 17 large wildfires burning in California on Wednesday, officials said.
Mariposa is about 150 miles east of San Jose, Calif. Large fires are now reported in 12 states, all in the western U.S.
Farther north in Mendocino County, about 450 firefighters tackled the 900-acre Grade fire.
Shelters were set up in schools, churches, and community centers for people and animals.
CalFire says it's also threatening power lines that supply electricity to Yosemite National Park.
People offered prayers on social media for the people of Mariposa.
The fire is being fueled by hot weather, heavy brush and tall grass, Cal Fire said. He saw the flames approaching from a ridge near his house southwest of Mariposa city on Tuesday morning.
MARIPOSA, CA - JULY 18: A firefighter monitors the Detwiler Fire on July 18, 2017 in Mariposa, California.
There were no immediate details on the structures destroyed or another listed as damaged. "We did have a problem earlier today with embers landing and creating spot fires outside of the area we have been concentrating on", Cal Fire Capt.
Known as the "Murphy Fire", having erupted near Murphy Springs, the event looked like trouble for a time on Monday. It is 49 percent contained after destroying 16 homes.