SONOMA, Calif. -- Vineyards moved their wine harvest to the cool of night and transit trains slowed for fear that some of the hottest weather in San Francisco Bay Area history would warp rails Saturday, as stifling temperatures and the smoky pall of wildfires marked an unofficial end to summer across the U.S. West.
In Los Angeles, a wildfire just north of downtown had grown to the largest in city history, Mayor Eric Garcetti said. Three structures had burned, at least two of them homes, but fire officials said they were confident they could tame the blaze unless winds picked up.
Wildfires also entered a 2,700-year-old grove of giant sequoia trees near Yosemite National Park and have driven people from their homes in Washington state, Oregon, Montana and other areas struggling with a weeklong heat wave that's gripped the region.
San Francisco, meanwhile, set a heat record for the day before noon, hitting 94 degrees. By mid-afternoon, it was 101 in the coastal city -- hotter than Phoenix. With an all-time high of 106 on Friday, it became just the third time since the 1870s that San Francisco had back-to-back triple-digit days.
Temperatures reached 115 south of the city.
Several hundred firefighters worked to contain the Los Angeles blaze, which prompted mandatory or voluntary evacuations for 730 homes in Los Angeles, Burbank and Glendale.
The fire was burning on multiple fronts southwest of the 210 Freeway, which remained closed Saturday morning between the Glendale Freeway and Sunland Boulevard.
"Our priority is saving people and saving property," Los Angeles Fire Department Chief Ralph Terrazas said at a news conference in Lake View Terrace, where he was joined by Garcetti.
"There is a lot of unburned fuel" in the area, Terrazas warned, noting that the last fire in the area was at least 30 years ago.
No injuries have been reported, officials said. At nearly 8 square miles, the fire had charred more land than any other in Los Angeles' history, Garcetti said.
Saturday night, Garcetti declared an emergency and asked the governor to do the same so state and federal assistance would be provided quickly.
"We can't recall anything larger," Terrazas said.
Resident Tracy Goldman said flames were about 200 feet from her house.
"It's very unsettling," she said as she watched, already having packed her car in case officials ordered her street to evacuate.
At one point, flames spread in four directions in intense heat and wild winds.
Officials said that if winds do not pick up, they were confident they could confine a blaze that was just 10 percent contained.
"Our biggest concern is the wind and weather," Terrazas said. "If there's no wind, this is a relatively easy fire to put out. But when the wind changes, it changes our priorities because other properties become at risk."
The heat wave battering most of California has intermittently knocked out power to thousands and helped fuel more than a dozen wildfires.
The weekend also broke heat records in wine counties north of San Francisco, where Labor Day for some vineyards marks the start of the busy grape harvest.
"We had been hoping for a mellow season," Kat Doescher, senior winemaker at Madrone Estate Winery outside Sonoma, said shortly after sunrise. She inspected the chardonnay grapes that workers had harvested overnight. "But I look at the forecasts, and I see a heat wave that's not getting any cooler."
Fires up and down California's Sierra Nevada and farther to the northwest cast an eerie yellow and gray haze.
Another wildfire burning near Yosemite had grown to 8.5 square miles and entered the Nelder Grove of 106 giant sequoias, despite firefighters' efforts to stave it off.
Fire officials said they had no immediate information Saturday on whether any of the giant trees -- including the 100-foot-round, 24-story-high Bull Buck sequoia -- had burned.
In the Pacific Northwest, high temperatures and a lack of rain this summer have dried out vegetation that fed on winter snow and springtime rain. Officials warned of wildfire danger as hot, dry, smoky days were forecast across Oregon and Washington over the holiday weekend.
A fire about 80 miles southeast of Seattle has burned more than 23 square miles and led to new evacuation notices Saturday. About 3,800 homes were threatened, authorities said.
Dozens of wildfires in Oregon were sending up large plumes of smoke, causing disruptions in holiday travel as roads close and shutting down camping areas.
Information for this article was contributed by Ellen Knickmeyer, Justin Pritchard and Martha Bellisle of The Associated Press; and by Ruben Vives, Andrea Castillo and Alene Tchekmedyian of the Los Angeles Times.
A Section on 09/03/2017