TUOLUMNE CITY — Crews are finally making progress against a massive U.S. wildfire burning near Yosemite National Park, fire officials said, and fears that the inferno could disrupt water or power to the city of San Francisco diminished.
While the fire continued to grow in size, containment numbers were up, Glen Stratton, an operations chief on the fire suppression team, said late Monday.
The fire was 20 percent contained, up from 7 percent hours earlier.
Officials said the fire had grown to about 725.2 sq. kilometers, up from about652.6 sq. kilometers the previous day.
Most of Yosemite, one of the country's most popular national parks, remained open to visitors.
Flames lapped at the edge of the main reservoir that supplies San Francisco, but the ash that has been raining onto the reservoir has not sunk as far as the water supply intake valves.
"It looks great out there. No concerns," Stratton said of the Hetch Hetchy Reservoir.
Nearly 3,700 firefighters battled the wildfire, the biggest on record in California's Sierra Nevada mountains.
The U.S. Forest Service said the fire was threatening about 4,500 structures and destroyed at least 23.
Heavy smoke settling low to the ground could limit visibility early Tuesday, but higher humidity was expected in the afternoon, which could help dampen the flames, said Matt Mehle, a National Weather Service meteorologist assigned to the fire.
California fire spokesman Daniel Berlant said crews were anticipating cooler temperatures and higher humidity this week that could allow them to gain control of the fire.
Rugged terrain, strong winds and dry conditions have hurt firefighters' efforts to contain the fire, which began Aug. 17. The cause has not been determined.