Officials also said about 1,500 homes are threatened by the flames. Some homes could already be seen burning.
Some structures have already been destroyed by the flames, but fire officials said they have not determined if they were homes or commercial buildings.
If the winds change directions, officials say thousands of homes in the San Fernando Valley could be threatened.
U.S. Forest Service spokesman Nathan Judy said some homeowners are trying to stay at their houses and fight the flames alongside firefighters in evacuation areas. In those cases, law enforcement is being called in to enforce the evacuations.
The blaze broke out Friday afternoon, starting at a small acreage before exploding to more than 3,000 acres by the evening hours.
Firefighters continued to battle the fire overnight and saw wild conditions that aren't typically present at night. Ground crews could not work on the fire and only helicopters and air tankers could try to control the fire.
"We were experiencing 50- to 100-foot flame links running across these ridges and down these slopes and doing the kind of things we normally expect to see at 2 p.m.," Los Angeles County Fire Department Battalion Chief Dennis Cross said. "It's been a really tough fire and a really tough fire season so far."
Crews are also concerned about the high temperatures and low humidity that could continue to fuel the fire. It is expected to be about 108 degrees in the area by the afternoon.
Evacuation orders were in effect for about 1,500 homes.
The evacuation areas included:
--All residents in Sand Canyon from Lost Canyon to Bear Divide (extended from Robinson Ranch Golf Course).
--All residents in Placerita Canyon from the Nature Center to Sand Canyon.
--Little Tujunga from Bear Divide to LA River Ranger District (Station), 12371 Little Tujunga Cyn Rd.
During a noon press conference, Los Angeles County Sheriff's Department Sgt. Burton Brink said the Sand Canyon area was on standby for possible evacuation orders.
The Red Cross opened an evacuation shelter at Golden Valley High School, 27051 Robert C. Lee Parkway, Santa Clarita.
Los Angeles Mayor Eric Garcetti also tweeted Friday that the Lake View Terrace Recreation Center, 11075 Foothill Blvd. in Lake View Terrace, would be an evacuation site for those affected by the blaze.
Large animals can be evacuated to Hansen Dam in Sylmar or the Jack Bones Equestrian Center, 26983 Tapia Canyon Road Castaic.
The Wildlife Waystation was evacuated Saturday and requested help from nearby residents to assist in moving as many of the wild animals as possible. In a Facebook post, the station said about 400 animals had to be moved out to safety. By Saturday afternoon, the animal sanctuary received enough help from volunteers.
One lane of the 14 Freeway remained closed as crews worked to suppress flames that were near the road, according to the Angeles National Forest Service.
Massive plumes of smoke billowed from the hillsides and could be seen throughout the Los Angeles region, from Orange County out to parts in the Inland Empire. The skies in many areas, especially the San Fernando Valley, were blanketed with thick, dark mounds of smoke and ash.
The South Coast Air Quality Management District issued a smoke advisory for parts of the San Fernando, San Gabriel and Santa Clarita valleys as well as central Los Angeles. The advisory is expected to expire by Saturday just before midnight, but it could be extended depending on how the blaze moves throughout the day.
So far, no injuries nor damage to property have been reported. For a full list of road closures, you can check http://dpw.lacounty.gov/roadclosures.
The cause of the fire is under investigation.