Firefighters, bulldozers and water tankers guarded homes close to a massive wildfire on Tuesday as officials urged rural residents of Southern California mountain communities to evacuate.
Thick smoke darkened the sky as flames rolled through pines and juniper trees on slopes of Los Padres National Forest, where more than 3,500 firefighters battled the fire that started on September 4.
No homes were lost to the fire, one of the largest and longest-burning wildfires in state history, burning some 70 miles (113 kilometres) northwest of Los Angeles.
Overall, containment was just 43 per cent.
Six unoccupied buildings were destroyed, including a modular home, a cabin, barns and trailers, said Dan Bastion, fire spokesman.
Wind-whipped flames jumped a road during the day, said Larry Comerford, a US Forest Service fire spokesman.
Water- and retardant-dropping helicopters and aircraft attacked the flames from the sky.
On the ground, a bulldozer ploughed a firebreak close to where the fires burned and at almost every house there was at least one engine and a few firefighters clearing brush, hosing down roofs and decks.
The new fire activity was a surprise setback for firefighters.
The blaze that had been moving relatively slowly with the dying of weekend Santa Ana winds that had the potential to greatly spread the flames but it did not.
The blaze, which has burned more than 144,880 acres (57,952 hectares) of wilderness, was ignited by someone burning debris.
Firefighting costs have topped 41 (m) million US dollars (euro32.3 million).
Governor Arnold Schwarzenegger declared a state of emergency for Ventura County.
The move cleared the way for government assistance with costs related to the fire.