Authorities on Wednesday warned 82,000 residents in San Bernardino County to evacuate from the fast-moving fire that began on Tuesday in Cajon Pass, a mountain pass between the San Bernardino Mountains and San Gabriel Mountains.
Some 34,500 homes were in the evacuation area, CNN reported.
The area of the massive blaze, called the Blue Cut Fire, is about 70 miles east of Los Angeles.
Weather conditions and the dryness of the brush have made the fire unpredictable.
"In my 40 years of fighting fire I have never seen a fire behavior so extreme as it was yesterday," CNN quoted Mike Wakoski, a fire official, as saying.
More than 1,500 personnel were on the scene responding to the blaze as well as 178 engines, 26 crews, 10 air tankers and 17 helicopters, according to the San Bernardino National Forest.
The massive fire has affected the Cajon Pass, Lytle Creek, Wrightwood, Oak Hills and surrounding areas. Governor Jerry Brown has declare a state of emergency in the area, CNN said.
"This is a very quickly growing wildfire," a San Bernardino National Forest statement said.
Drought-stricken California has been hit with waves of wildfires this year, fueled by dry conditions, heat and dead brush.
Before the Blue Cut Fire, 8,000 firefighters had already battled eight large wildfires across the state, CNN added.
