(Updates fire information; adds quote, byline)

By Anupreeta Das

SAN FRANCISCO, July 27 (Reuters) - An out-of-control wildfire near one of the entrances to Yosemite National Park charred more than 18,000 acres, destroyed eight houses and has put about 2,000 homes at risk, fire officials said on Sunday.

Firefighters were able to control about 16 percent of the blaze, dubbed the "Telegraph Fire," which began Friday afternoon, said Wayne Barringer, an information officer at the California Department for Forestry and Fire Prevention.

Seven outbuildings, including barns and sheds, were also destroyed, but there have been no reported injuries, said another officer, Daniel Berlant.

The fire has not seen any "major movement" in the past 12 hours, but remains "very active" on the south flank toward Mariposa, a town of about 1,800 inhabitants, and on the east flank toward Yosemite, according to the department's Web site.

"It's tolerable today, but yesterday afternoon, there was a lot of ash falling down" in Mariposa, Barringer said.

"The fire's going in all directions," said Berlant. "There are reports of flame lengths over 100 feet (30 meters)."

About 195 homes in the towns of Midpines and Coulterville were under mandatory evacuation orders, officials said.

Midpines is a tiny community of about 600 people along one of the main highways to Yosemite, the storied 1,200-square-mile (310,800 hectares) park in central California that gets nearly 4 million visitors a year.

The fire is not affecting the park itself, but power supply to Yosemite Valley, an area that includes popular sightseeing spots like El Capitan, has been cut off, said Julie Chavez, a Yosemite media relations officer.

"We're running on generators," she said, adding that all four entrances to the park and major roads remain open. But "air quality and visibility have been impeded," Chavez said.

Berlant said the fire was caused by a spark from a person shooting at targets and was fueled by dry timber that has not burned for 100 years. "There's a lot of fuel for the fire burn," he said.

There are about 2,000 firefighters battling the blaze, along with 200 fire engines, 12 air tankers and 12 helicopters. A big challenge to controlling the fire is steep, rugged terrain that makes access difficult, Berlant said. (Reporting by Anupreeta Das, editing by Chris Wilson)

AlertNet news is provided by