LOS ANGELES — The flames raced across brittle hillsides like advancing armies. Up and down Southern California’s canyons and coastlines, they stormed into neighborhoods and engulfed homes where people were using sprinklers and garden hoses as a last, desperate defense against the wind-driven wildfires.

On Thursday, the hot, dry winds sparked new fires in San Diego and Riverside Counties and up the coast. Nearly 200,000 people were forced to evacuate, and residents in areas already charred by wildfire worried that the strengthening, erratic winds could ignite new fires at any moment.

Fire and smoke forced intermittent closures of the 101 freeway — the main coastal route north from Los Angeles — between Ventura and Santa Barbara, along with several secondary highways and smaller roads. On Wednesday, it had been portions of the 405 freeway closed, which sent long lines of traffic onto surface streets.

Several new fires cropped up, including one in San Diego County that spread to more than 2,000 acres in five hours, destroying and damaging a relatively small number of homes but threatening at least 1,000 more.

Across the region, people wiped stinging smoke from their eyes and huddled inside to avoid the scrim of acrid air. They stood in their front yards and prayed. They sifted through their charred homes, fled to evacuation shelters and said that even in this wildfire-prone state, they had never confronted late-season blazes as fast and ferocious as these.

“We’ve always been under threat of fire; we’re used to it,” said Suzanne White, who drove past curtains of flames above the 101 freeway as she fled her home in the mountain-fringed town of Ojai. “But this year, the fires are raging so fast and furiously that you can’t get ahead of them.”

“It burns,” she said, “and it keeps burning.”

Some people agonized over whether to stay and defend their homes or join the thousands who had already evacuated. Along Faria Beach, on the edge of the Pacific in Ventura, Steve Andruszkewicz, 75, and his wife, Gloria, had packed both cars in case the firefighters battling spot blazes nearby told them to go.