Residents of more than 500 homes have been ordered to evacuate a densely populated area just outside Los Angeles as four large wildfires swept across southern California, officials said.
By late Thursday, the blaze in La Canada Flintridge -- some 15 miles (24 kilometers) north of Los Angeles -- had almost doubled in size to over 500 acres (202 hectares) and was only five percent contained, the US Forest Service said.
It had ordered a mandatory evacuation order for more than 500 homes north of Vista Del Valle Road, east of La Canada Boulevard and extending into La Canada Country Club area.
"The fire is making a run. It's spreading fast," US Forest Service spokeswoman Dianne Cahir told the Los Angeles Times.
A Los Angeles County Fire Inspector Frederic Stowers told AFP that over 500 firefighters, four aircraft and eight helicopters were battling the fire that was fuelled by dense, dry brush in steep terrain.
In Portuguese Bend on the Palos Verdes Peninsula, a wildfire had slowed down after burning 75 acres (30 hectares) and could force up to 3,000 people to evacuate, Stowers said, noting that over 300 firefighters, about 70 fire engines and five helicopters were seeking to tame the fire.
It was feeding on the same type of topography as the La Canada blaze.
Meanwhile, a fire charred some 600 acres (243 hectares) in the San Bernardino National Forest east of Hemet -- some 90 miles (145 kilometers) east of Los Angeles -- but did not appear to threaten homes.
Firefighters were making progress in taming the fourth blaze, dubbed the Morris fire, which began Tuesday and has burnt through 2,000 acres (809 hectares). By late Thursday, it was 60 percent contained, authorities said.
The San Gabriel Valley, which lies to the east of Los Angeles, experienced record heat and low humidity, with temperatures soaring above 100 degrees Fahrenheit (38 degrees Celsius) in the warmest locations, the National Weather Service said in its red flag warning for the region.
California is frequently hit by wildfires and in 2007 suffered the worst blazes in its history, which forced the evacuation of 640,000 residents and destroyed around 2,000 homes in southern California.