Gusts reaching 70mph have fuelled the spread of a California wildfire, one of several which has forced residents to flee their homes.
The biggest blaze began late on Wednesday as a house fire in Orange County’s Silverado Canyon, and the fire has since grown to 11 square miles.
“When crews arrived it was a fully engulfed house and the winds were extremely strong and they pushed flames into the vegetation,” said Colleen Windsor, a spokeswoman for the county’s Fire Authority.
Crews struggled in steep terrain amid unpredictable Santa Ana winds that sent flames racing across major roads.
Two firefighters were taken to hospital after being treated on scene for injuries, said Fire Chief Brian Fennessy, and their condition is not yet known.
Some homes were damaged in the fire and possibly destroyed, Mr Fennessy said.
Evacuations were ordered for thousands of residents of canyon and foothill neighbourhoods near the city of Lake Forest – although some orders were later lifted – and residents of other nearby areas were told to be ready to get out.
Numerous studies have linked bigger wildfires in America to climate change from the burning of coal, oil and gas.
Scientists have said climate change has made California much drier, meaning trees and other plants are more flammable.
The Bond Fire about 50 miles southeast of Los Angeles is burning near the same area of October’s Silverado Fire, which forced tens of thousands of people to evacuate.
The new blaze broke out as Southern California utilities cut the power to tens of thousands of customers to avoid the threat of wildfires during the notorious Santa Ana winds.
Red flag warnings of extreme fire danger which run through until Saturday were in place because of low humidity, bone-dry brush and the winds, which sweep down from the interior, the National Weather Service said.
California already has experienced its worst-ever year for wildfires.
More than 6,500 square miles have been burnt, a total larger than the combined area of Connecticut and Rhode Island.
At least 31 people have been killed and 10,500 homes and other structures damaged or destroyed.
The latest fire threat comes as much of California plunges deeper into drought. Virtually all of Northern California is in severe or extreme drought while nearly all of Southern California is abnormally dry or worse.