TUOLUMNE CITY, Calif. (AP) — Crews were finally gaining ground on a massive wildfire burning near Yosemite National Park and no water or power disruptions were expected from ash raining on the main reservoir that supplies San Francisco, officials said late Monday.
While the blaze continued to grow in size, containment numbers were up, as was optimism that firefighters were making some progress, said Glen Stratton, an operations chief on the fire suppression team.
Nearly 3,700 firefighters battled the approximately 252-square-mile blaze, the biggest wildfire on record in California's Sierra Nevada. The fire was 20 percent contained.
"It's been a real tiger," said Lee Bentley, fire spokesman for the U.S. Forest Service. "He's been going around trying to bite its own tail, and it won't let go but we'll get there."
While flames reached the edge of the Hetch Hetchy Reservoir, the chief source of San Francisco's famously pure drinking water, crews were confident they would be able to protect hydroelectric transmission lines and other utility facilities, Stratton said.
Utility officials monitored the clarity of the water and used a massive new $4.6 billion gravity-operated pipeline system to move water quickly to reservoirs closer to the big city.
"It looks great out there," Stratton said Monday night. "I don't think we're going to have any problems up at Hetch Hetchy."
So far the ash that has been raining onto the reservoir has not sunk as far as the intake valves, which are about halfway down the 300-foot O'Shaughnessy Dam. Utility officials said that the ash is non-toxic but that the city will begin filtering water for customers if problems are detected. That could cost more.
Power generation at the reservoir was shut down last week so that firefighters would not be imperiled by live wires. San Francisco is buying replacement power from other sources to run City Hall and other municipal buildings.