Traffic makes their way south on I-15 as ash from the Holy Fire fills the air on Aug. 9, 2018 in Lake Elsinore, Calif.
Traffic makes their way south on I-15 as ash from the Holy Fire fills the air on Aug. 9, 2018 in Lake Elsinore, Calif.

Firefighters were working furiously Friday night to keep a Southern California wildfire away from homes. The fire in the Cleveland National Forest is threatening thousands of homes south of Los Angeles and has grown in size to nearly 77 square kilometers.

On Thursday night, California Governor Jerry Brown declared a state of emergency in Orange and Riverside counties, where the fire is burning.

Overall, nearly 20 fires are burning in California. Ten people have died as a result. In Southern California, about 20,000 residents have been forced to evacuate.

Some residents have refused to go, saying they will stay behind to protect their homes.

King Bass, 6 (L) sits and watches the Holy Fire bu
King Bass, 6, sits and watches a fire burn from on top of his parents' car as his sister Princess, 5, rests her head on his shoulder, Aug. 9, 2018 in Lake Elsinore, Calif.

Trabuco Canyon resident Forrest Clark, 51, arrested earlier this week, was charged Thursday with three counts of felony arson. Local reports say the suspect two weeks ago sent an email to a volunteer fire chief in the area, saying "this place is going to burn."

The chief, Mike Mulligan, told CNN he has known Clark for decades and has been warning for a long time that Clark posed a danger to the community.

This year's fire season is shaping up to be one of California's worst. In northern California, the Mendocino Complex Fire has become the largest fire in state history and burned more than 100 homes. It is now 60 percent contained.

So far, it has burned an area the size of Los Angeles, and officials say it may be September before they are able to contain it.

This satellite image released on Aug. 7, 2018 prov
This satellite image released on Aug. 7, 2018 provided by NOAA shows the wildfires known as the Mendocino Complex, Calif. Northern California is grappling with the largest wildfire in California history, breaking a record set only months earlier.

The blaze is made up of two separate fires burning in the northern Mendocino and Lake counties that have merged.

The California Department of Forestry and Fire Protection (CAL FIRE) had anticipated that the blaze could be fully contained by August 15, but now say it will be September 1.


WATCH: California Forest Fires Threatening More Homes

Officials say some 14,000 firefighters, including inmates and firefighters from overseas, have managed to build containment cut lines around half the fire to contain the flames burning about 160 kilometers north of San Francisco.

Those lines have kept the southern edge of the fire from spreading into residential areas on the east side of Clear Lake. But CAL FIRE said the flames are out of control to the north, roaring into remote and unpopulated areas of thick forests as firefighters contend with record-setting temperatures.