The so-called Tick Fire near Santa Clarita, 65km (40 miles) north of Los Angeles, broke out on Thursday and quickly consumed 2,023 hectares (5,000 acres), fire officials said.
The blaze burned several homes and structures and forced the closure of a major highway and a number of roads, as about 500 firefighters backed by air tankers and helicopters battled the flames.
There were no immediate reports of casualties.
“We are urging everybody to evacuate at this time,” a spokesman for the fire department said.
The fire erupted as much of the state was under a red-flag warning because of gusty winds, high temperatures, and low humidity that make for perfect wildfire conditions.
In northern California wine country, about 2,000 people were ordered to evacuate after a brush fire erupted late on Wednesday, California fire officials said.
About 500 responders battled the blaze fed by wind gusts topping 113km/h (70 miles/h).
Mandatory evacuation orders were issued for the community of Geyserville and nearby vineyards after the fire started in a mountainous area and quickly spread, crossing a highway and moving towards homes, the Sonoma County Sheriff’s Office said.
“If you’re in Geyserville, leave now,” the sheriff’s office advised, citing an extraordinary threat to life and property.
Winds out of the north were driving the blaze as firefighters struggled to save homes.
On Friday, the fire was five percent contained and several structures had burned, officials said.
The blaze – 120km (75 miles) north of San Francisco – came amid official warnings that much of northern California and parts of the south were under imminent threat because of blustery, dry weather and high temperatures.
Another brush fire in San Bernardino County, about 96km (60 miles) east of Los Angeles, also prompted evacuation orders as it quickly burned 30 hectares (75 acres).