A man has been arrested on suspicion of arson over one of the fires burning in California.
Around a dozen homes and 10 miles of brush and timber have been destroyed by the blaze south of Los Angeles.
1,500 residents in the north of the state are still under a mandatory evacuation order because of the wild blazes.
14,000 firefighters are battling 18 fires that have carved their way through forest land and are threatening urban areas.
"For whatever reason, fires are burning much more intensely, much more quickly than they were before," said Mark A Hartwig, president of the California Fire Chiefs Association.
Some of the largest fires have erupted within the past few weeks as the state has seen record-breaking temperatures - and the historically worst months of wildfire season are still to come.
In northern California, the record breaking Mendocino Complex - twin fires being fought as a single conflagration - gained ground on Tuesday but more slowly because its own smoke covered the area and lowered the temperature, according to the California Department of Forestry.
The flames, which had burned 457 square miles, were raging in mostly remote areas and no deaths or serious injuries were reported but 75 homes were destroyed.
The blaze, which broke out on July 27, initially spread quickly because of what officials said was a perfect combination of weather, rugged topography and abundant brush and timber turned to tinder by years of drought.
PA & Digital Desk