Retirement communities built on golf courses, semi-rural race horse stables and other usually serene sites were engulfed by flames as the San Diego area became the latest front in California's wildfire fight.
Races at the Los Alamitos Race Course were cancelled on Friday as the racing community mourned for at least 30 horses believed to have died.
Fires that have raged around Los Angeles this week spread to the San Diego area on Thursday amid unusually dry, hot, windy conditions across the region.
The new blaze covered more than 16 square kilometres in a matter of hours and burned dozens of houses as it tore through the tightly packed Rancho Monserate Country Club community in the small city of Fallbrook, known for its avocado orchards and horse ranches. Three people were burnt while escaping the flames, a fire and forestry official said.
California fires threaten Murdoch estate in wealthy Bel Air area
Wildfires rip through California communities
Meanwhile, firefighters in Ventura, 209km to the north, tried to corral the largest and most destructive fire in the state, which has destroyed 430 buildings. The so-called Thomas Fire has grown to 180 square miles (466 square kilometers) since it broke out Monday. Fire crews made enough progress against large fires around Los Angeles to lift most evacuation orders.
The fire north of San Diego, driven by winds above 50 kph, razed rows of trailer homes in the retirement community, leaving charred and mangled metal in its wake.
It was not immediately known what sparked the fire next to State Highway 76, but strong winds carried it across six lanes to the other side.
Evacuations were ordered in the area near the Camp Pendleton Marine Corps Base and schools and casinos were being used as shelters.
Cynthia Olvera, 20, took shelter at Fallbrook High School.
She had been at her Bonsall home with her younger sister and nephew when her father called from the family nursery to say the fire had reached the gate of their sprawling property.
After starting to drive away, the family turned around to recover forgotten personal documents — but it was too late. Trees were ablaze and flames were within three metres of the house.
"I didn't think it would move that fast," she said.
Her older sister wanted to drive in to save her husband's car, but Ms Olvera told her: "Don't do it. It's not worth it."
Her sister heeded the advice and the family made it safely to the school. But the flames followed them, and the family had to pack up again when evacuation orders came for Fallbrook High School.
The family went to a second shelter, not knowing if their house survived.
As the flames approached the elite San Luis Rey Downs training facility for thoroughbreds, many of the more than 450 horses were cut loose to prevent them from being trapped in their stables if barns caught fire, said Mac McBride of the Del Mar Thoroughbred Club.
Herds of horses galloped past flaming palm trees in their chaotic escape. Not all survived, although it was not clear how many had perished.
Horse trainer Scott Hansen said he knew that at least 30 horses at the facility had died.
"I don't know how many are living and how many are dead," he said. "I guess I'll have to figure that out in the morning."
Along the coast between Ventura and Santa Barbara, tiny beach communities were under siege as fires leapt from steep hillsides across Highway 101.
"We drove through a wall of flames," Wendy Frank said, describing her ordeal after evacuating her horses from Ojai on Wednesday night. "I didn't know if we'd make it. I just put the accelerator down ... and just hoped for the best."
Fires flared up along the highway on Thursday, forcing an evacuation of dozens of homes at Faria Beach.
The massive fire threatened Ojai, a scenic mountain town of 7,000 people dubbed "Shangri-La" and known for its boutique hotels and New Age spiritual retreats.
Ash fell like snow on citrus orchards scattered around town and on Spanish-style architecture as firefighters parked their trucks around houses in anticipation of winds picking back up.