Southern California wildfires have nearly tripled in size inside 24 hours, engulfing an area of 43 sq miles.
Firefighters have been using engines, aircraft, bulldozers and other equipment to battle the flames 50 miles north-west of Los Angeles.
Dubbed the Springs Fire, it has damaged just 15 properties but thousands of others are at risk.
Firefighters are counting on cooler weather and rain to help control it.
Captain Mike Lindbery of the Ventura County Fire Department said early on Saturday that crews intended to take advantage of the change in the weather.
“That will give us a chance because it’s going to really bring that fire activity down quite a bit,” he said.
“I think we will make some significant progress.”
After breaking out on Thursday, the fire quickly swept through the Camarillo Springs area.
It forced the closure of a section of the Pacific Coast Highway and threatened a naval facility.
Some 1,000 firefighters were deployed to fight it.
Local people were grateful so many homes had escaped the blaze.
Properties in the Springs area were well prepared for the fire after years of planning. Homes were built with sprinkler systems and fireproof exteriors from the roofs to the foundations.
Residents are required to clear brush and other combustible materials to within 100ft of the dwellings and local roads were built wide enough to accommodate emergency vehicles.
It is more usual for such wildfires to flare up in September or October, after the summer has dried out hillside vegetation, but the region saw a severe drought during the past year.
Fire crews have tackled more than 680 wildfires in California so far this year, some 200 more than average for the period.
Other fires have been burning this week in Riverside County, in the hills above Glendale and in Tehama County, northern California.