Gov Arnold Schwarzenegger says the number of fires has been "overwhelming"
Crews battling wildfires in California have made some progress containing the two biggest fires near the towns of Goleta and Big Sur, officials said.
Firefighters in the Goleta area are now working on preventing the flames from reaching nearby Santa Barbara.
Crews further up the coast at Big Sur have so far defended the scenic town, helped by cool, moist weather.
In the past two weeks, hundreds of fires, most started by lightning, have burnt 820 sq miles (2,100 sq km).
The blazes have destroyed 67 houses or other buildings and contributed to the death of one firefighter who had a heart attack while building a fire-break.
About 20,000 people, many of them volunteers, have been fighting the fires.
"The firefighters are stretched thin, they are exhausted," said California Governor Arnold Schwarzenegger.
Officials have described the combination of dry brush and trees, dry weather and windy conditions as a "perfect storm".
Authorities had declared the Gap Fire, 100 miles (160km) north-west of Los Angeles, the priority blaze as it encroached on the town of Goleta on Friday.
Nearly 1,200 firefighters backed by 10 aircraft dropping fire retardant material have contained about 24% of the fire.
"It's looking really good," said Manuel Madrigal, a spokesman for the joint federal, state and local fire crews in the area.
"The crews are in there cleaning up, mopping up and looking for hot spots," he said.
The focus was now on preventing the fire from shifting to the east, through an area of housing estates, orchards and rugged canyons full of dry brush, towards Santa Barbara.
A spokesman for Santa Barbara County said residents of nearly 2,700 homes were under mandatory evacuation order and people in another 1,400 homes had been told to be ready to flee on short notice.
Cooler weather and a morning fog on Saturday helped crews further north working to save the tourist town of Big Sur from another major fire.
Twenty homes have already been destroyed by the fire, which has steadily advanced towards the town over the past two weeks.
Officials said the fire was 5% contained.
"We're gaining ground, but we're nowhere near being done," said Greg DeNitto, of the US Forest Service.
Aerial footage of the US wildfires
Residents of the area described the fire's progress to the BBC.
"When the fog cleared we saw this beautiful sky with a huge plume of smoke. As it approached we could see hot flames, burning and redness," said Judyth Greenburgh.
She has been evacuated twice in the past two weeks as the fire advanced.
"The wind changes very quickly so one minute you can see it and the next you don't."
Erica Buffet's ranch was issued with a mandatory evacuation notice.
"The fire was about two miles south-east of us the night before the mandatory evacuation. We watched from the top of the ranch and there were flames coming over the ridge, huge flames, it was definitely on its way," she told the BBC.
"But what is scary about this fire is that it is bigger than past fires people around here have dealt with."
Governor Schwarzenegger said the state's fire season, formerly lasting from late summer through the autumn, was now year-round.
He said the state now needed more resources to battle the increase in wildfires.
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