Firefighters responded Thursday afternoon to a brush fire in northern Los Angeles County.
The Alta Fire was reported east of the 5 Freeway in the Neenach area, about 45 miles north of Santa Clarita. The fire was at about 330 acres early Thursday afternoon before forward progress was stopped.
Flames were threatening buildings, one of which appeared to be on fire. It was not immediately clear how many homes or businesses are in the area north of Los Angeles.
The fire is one of at least three that have started this week in Southern California, including the Sandy Fire in Ventura County and two fires in Riverside County.
The fires led to a smoke advisory for parts of the region that was set to expire Thursday night.