A brush fire in the Santa Clarita area increased in size to 421 acres overnight and was about 10% contained Wednesday, authorities said.
The Agua Fire was reported shortly after 2 p.m. Tuesday in the area of Soledad Canyon and Agua Dulce Canyon roads, according to the Los Angeles County Fire Department. The fire burned into the Angeles National Forest, and county fire crews were joined on the lines by U.S. Forest Service firefighters.
Crews were battling the flames in triple-digit temperatures that prompted the National Weather Service to issue a heat advisory for the Santa Clarita Valley.
The fire was initially estimated at 4 acres, but crews on the scene warned that it had the potential to spread across as many as 200 acres. A second alarm was quickly called, summoning additional crews to the scene.
One firefighter was treated for unspecified minor injuries suffered while fighting the blaze. Nearby Metrolink tracks were closed as a precaution.
Power lines and some structures were threatened by the flames, and crews on scene indicated a trailer park in the area might be endangered.
According to forest service officials, the fire was about 10% contained at 7:10 p.m. Tuesday. As of about 9 a.m. Wednesday, that figure had remained the same, although the size of the fire had increased to 421 acres. Officials attributed the growth to steep terrain and difficult access.
No evacuations have been ordered, but Soledad Canyon Road was closed between Agua Dulce Road and Crown Valley Road, the forest service reported.
The cause of the fire was not immediately known.