The blaze, dubbed the Sage Fire, broke out Saturday at about noon near Sagecrest Circle and The Old Road.
Los Angeles County fire officials said the flames had quickly spread to 800 acres by Saturday afternoon, and by morning on Sunday, the fire grew to 1,100 acres.
More than 1,200 firefighters from the ground and air were battling the fast-moving blaze, leading them to contain about 20 percent of the fire by the morning hours.
As of Sunday evening, one structure had been damaged as crews relied on a heavy use of fire retardant dropped by aircraft to help keep flames away from homes.
Wind and low humidity, however, prompted a red-flag warning for most of Southern California on Sunday, making the firefighting effort much tougher in the area.
The South Coast Air Quality Management District issued an air quality alert and recommended people living and working in the Pomona area and Santa Clarita Valley area with heart disease, asthma or other respiratory diseases to minimize outdoor activities.
At least 700 homes were under evacuation orders Saturday night, county fire officials said.
The areas under evacuation included the community of Morning Mist; areas along Old Stone Way south of Pico Canyon Road, including Southern Oaks Drive between Greensbrier Drive and Meadow Lane; Autumn Place, Shady Glen Court and Magnolia Lane west of Oakridge.
Other evacuations included: Hazlecrest Lane, Bracken Lane, Laurel Crest Lane, Sagecrest to Smokewood Way, Summerhill Lane, SouthWind Court and Jasmine Lane.
Backfires helped firefighters move flames away from homes, and by 9:30 p.m., officials lifted evacuation orders, allowing about 2,000 people to return home.
Officials said an evacuation center at West Ranch High School was shut down. Only residents with identification would be allowed back in, and no trailers, boats or recreational vehicles would be allowed initially, they said.
The cause of the blaze was under investigation. null