Hard-pressed firefighters in California are facing a fresh crisis as strong winds triggered more wildfires in the south of the state.
A blaze sprang up in California’s Simi Valley early on Wednesday and tripled in size in two hours.
The flames were driven by gusts of wind approaching hurricane-level speeds, over 74mph (119km/h).
Later in the day, more than a dozen other wildfires sprang up around the city’s suburbs.
Fires across California over the past week have led to mass evacuations and power cuts. Governor Gavin Newsom has declared a state-wide emergency.
At one point on Wednesday the fire in the Simi Valley – named the Easy Fire – threatened to engulf the Ronald Reagan Presidential Library.
As the so-called Santa Ana winds swept in, the National Weather Service issued rare “extreme red flag” warnings for Los Angeles and Ventura counties.
“I don’t know if I’ve ever seen us use this warning,” said forecaster Marc Chenard.
Palls of smoke from the wildfires could be seen from the International Space Station.
Ventura County Fire Chief Mark Lorenzen told a news conference that the Easy Fire now covered 1,600 acres (647 ha).
“We have upwards of 1,000 firefighters on the line right now protecting the community,” he said.
“We continue to have strong winds, there’s still significant risk out there.”
He warned the public to “stay aware and be prepared for evacuation”.
“That’s still a possibility. We still are not through this. We have another 24 hours of significant weather conditions and a lot of threat,” he added.
Aircraft carrying water and fire-retardant joined the effort to protect the Ronald Reagan Presidential Library, which is about 40 miles north-west of LA.
Staff were advised to “shelter in place” as emergency crews tackled the flames. Library director Duke Blackwood later announced that the building was out of danger. He said artefacts had already been moved to safety to protect them.
It was later revealed that a herd of goats probably helped to save the hilltop library.
They had been hired to eat an area of flammable shrubs earlier this year, creating a fire break.
Ventura County’s assistant fire chief Chad Cook said the Easy Fire had quickly “outflanked” crews fanned by the winds.
“We did experience gusts up to 65mph this morning which made long-range spotting very, very dangerous and also quickly outpaced the initial attack resources,” he said.
There are fears that the winds will also fan the nearby Getty Fire, which has already scorched 745 acres.
Meanwhile, authorities in northern California said progress had been made in tackling the Kincade Fire which ignited last week.
The fire covered 76,825 acres and triggered evacuation orders for nearly 200,000 people.
On Wednesday, officials said the blaze was 30% contained.
Meanwhile, energy supplier Pacific Gas & Electric (PG&E) cut off power to nearly 400,000 more homes across California on Wednesday as a precaution against damaged power cables starting more fires.
The utility has come in for strong criticism for pre-emptively shutting off power to thousands of properties.
The company says it is a matter of public safety but critics say the precautionary blackouts have been too widespread and too disruptive.
PG&E filed for bankruptcy in January after facing hundreds of lawsuits from victims of wildfires in 2017 and 2018.