The blaze began shortly before 5 p.m. PST on Friday, according to CNN affiliate KABC-TV. No injuries were reported.
A single-family house and two outbuildings were destroyed by the fire, firefighters tweeted.
Evacuation centers have been set up at local hotels and at Beaumont High School, firefighter spokesman Rob Roseen told CNN.
All evacuation centers will apply COVID-19 protocols such as entrance temperature checks, masks and social distancing, Roseen said.
As of Saturday night, the fire burned about 12,000 acres and is brought under control to zero, according to firefighters. The cause of the fire remains under investigation.
There is increased potential for plume growth with fires this weekend due to warm temperatures, very low humidity and offshore winds, according to the National Weather Service.