Record Heat in Southern California, and an Ominous Start to Wildfire Season

LOS ANGELES — After a temperate early summer and a balmy Fourth of July, Southern California residents abruptly found themselves in a caldron of triple-digit temperatures and wildfires this weekend.

Firefighters across the region battled several blazes through the night Friday into Saturday, as an unseasonable heat wave set records in some places and knocked out power to tens of thousands of homes in Los Angeles.

In Santa Barbara County, nearly two dozen homes were incinerated in a wildfire that began Saturday, once again harrowing an area ravaged in the last year by fires and then mudslides that killed 21 people.

No deaths were reported on Saturday, but the county said the fire was “causing conditions of extreme peril to the safety of persons and property.” Gov. Jerry Brown declared a state of emergency in Santa Barbara County, mobilizing state resources against the fire.

In the San Diego area, some residents took to the beaches to cool off from temperatures as high as 115, while others, in the communities of Dulzura, Alpine and the Camp Pendleton Marine Corps base, fled wildfires or tried to save their homes.

“Historically, fire season in San Diego has occurred during the fall, when the Santa Ana winds come charging through the brush fueling wildfires, but now San Diegans are experiencing fire season year-round,” said George Lucia, a retired fire chief who worked in several cities in the county.

“San Diego has been in a long drought,” Mr. Lucia added, “and the recent rains that we had didn’t help; they just ran off into tributaries.”

The fire in San Diego, called the West Fire, began on Friday along Interstate 8, and firefighters were seen running alongside the highway, battling a wall of flames as cars rushed by. On Saturday morning, officials said they had contained 30 percent of the fire, which has burned 400 acres.

The scenes across the region underscored worries among officials and scientists that fire season would come earlier to California this year, amid drought conditions, raising worries of a destructive season ahead. Last year was the deadliest and costliest fire season in the state’s history; in October, the worst of the season’s fires raged in Northern California, burning through wine country. Last year 44 people were killed in California wildfires, which brought destruction estimated at $10 billion.

The National Weather Service had an extreme heat warning in place in Southern California until Saturday night, and officials urged residents to cool off in libraries and city pools.

The heat was especially hard on the homeless in Los Angeles, who number in the tens of thousands. Destiny Galbreath was already sweating when she woke up on Saturday in her tent in downtown Pomona, in the eastern part of the county, where temperatures reached 105. Ms. Galbreath, 23, said the heat was much harder to take than the cold.

“When you’re outside in the cold, it’s easier because everyone comes together,” she said. “Everyone tries to huddle up.”

Ms. Galbreath was waiting for the library to open — for the sweet relief of air conditioning. She held a foam cup that a local restaurant would later fill with ice for her.

The temperature spike broke with historical weather patterns. While much of the Northern Hemisphere suffers through its hottest days in the summer months — June, July, August — Southern California’s hottest days are often in September or October.

Records were shattered in some places on Friday. The temperature at the University of California, Los Angeles, reached 111 on Friday, the hottest it has ever been there. Other record highs, according to the National Weather Service, were 114 at the Hollywood Burbank Airport, 117 at the Van Nuys Airport, 117 in Ramona and 114 in Santa Ana. In Riverside, a high temperature of 118 matched a record set in 1925.

Many sidewalks and plazas in the region were ghost towns, and the hum of air-conditioners filled the heavy, ovenlike air.

In a park in San Dimas, Dyani Yanez-Rios was laying out Super Soakers for her 5-year-old son’s birthday party, and a heat wave was not going to stop it. Temperatures topped 110 on Friday, but she was hoping for the best on Saturday.

“Yesterday really bummed us out,” she said. “Today it’s only supposed to be 105 from noon to one. Nobody’s called to cancel so far!”

Power failures only amplified the suffering. Even dog shelters were putting out calls for volunteers and supplies. Kacey Montoya, a reporter for KTLA, a local news station, wrote on Twitter that at one shelter in Los Angeles, “the heat conditions are unbearable for the dogs in kennels. The shelter is in desperate need of volunteers, old towels, ice and hard plastic children’s pools!”

(At least some animals found respite from the punishing temperatures; the Los Angeles Zoo shared photographs on Twitter of some of its residents dunking themselves in water, to the jealousy of many.)

Daniel Swain, a climate scientist at U.C.L.A., said the heat in California was part of the same high-pressure weather system that brought scorching temperatures to the East Coast earlier in the week, and then expanded westward.

Mr. Swain has written about extreme weather patterns in California, and how they have shaped the state’s history. The standard pattern is a drought during the summer, with much of the state’s annual rainfall coming in torrents over a few winter days. Heat waves in recent years have become more intense, a consequence of global warming, he said, raising the possibility of ever-deadlier fire seasons.

“The overall trend over decades to more intense and more frequent heat waves is definitely a signal of global warming,” Mr. Swain said.

The current heat in Southern California was especially unusual, he said, because some areas closer to the coasts were hotter than, or comparable to, temperatures in the inland deserts. The reason is an unusual wind pattern: Instead of cool coastal breezes, hot downward-sloping winds were blowing from the mountains toward the coast.