MIDPINES, Calif. — An out-of-control wildfire burning Sunday near an entrance to Yosemite National Park has destroyed eight homes and threatened thousands more as flames forced authorities to cut power to the park.

The blaze has charred more than 18,000 acres since Friday as wooded slopes ignited amid hot, dry conditions that have plagued California for months. The fire was completely uncontained Sunday.

"There's no fire history in the past 100 hundred years. That's one of the reasons this fire's been able to burn so erratically," said Daniel Berlant, spokesman for the California Department of Forestry and Fire Protection.

In Southern California, visitors were evacuated Sunday from the Los Angeles zoo as a fast-moving brush fire burned nearby in Griffith Park.

The five-acre blaze burned within about 1,000 feet of a California condor enclosure. The rare birds were not in immediate danger and fire fighters were on hand to protect the cages.

About 200 firefighters were at the scene, Los Angeles Fire Department spokesman Ron Myers said.

Griffith Park, one of the largest urban parks in the U.S., was closed, a city dispatcher said.

Meanwhile, near Yosemite National Park, the wildfire led officials to order the evacuations of 170 homes under immediate threat. About 2,000 homes faced at least some danger from the fast-spreading flames, according to fire officials. No injuries were reported.

Flames towered as high as 100 feet on Saturday but had scaled back Sunday as temperatures cooled and winds calmed, Berlant said.

State fire spokeswoman Karen Guillemin said the blaze was sparked by someone target shooting but would not elaborate.

About 2,000 firefighters were battling the blaze and hundreds more were headed to the scene along the Merced River west of Yosemite, one of the nation's most visited national parks.

Most of the evacuated homes are in the town of Midpines, located along Highway 140, about 12 miles from the park. The southern edge of the blaze was as little as two miles from Mariposa, a town of about 1,800 residents, Berlant said.

Billowing smoke from the wildfire has cast a noticeable haze over much of the park, including the famed Yosemite Valley, park spokeswoman Julie Chavez said.

To protect firefighters battling flames beneath power lines, electricity was cut to a wide area, including the national park, fire officials said. Some park buildings were closed because of the power outage, but generators were still providing hotels, stores and other heavily used park facilities with electricity, Chavez said.

The park will likely remain without an outside source of power for several days until crews can repair a transmission line brought down by the fire after power was cut, said James Guidi, a spokesman for Pacific Gas & Electric.