"Human activity" is what the LA Times is reporting is the cause of the fires. That's arson if it wasn't an accident.

The most destructive fire in Malibu in nearly 15 years raced through parched canyons Saturday, consuming 49 homes and forcing the evacuation of thousands of residents.

The so-called Corral fire burned 4,700 acres before the fierce Santa Ana winds died down, allowing firefighters to make a stand. By evening, the blaze, which investigators said was started by "human activity," was 25% contained. Six firefighters sustained minor injuries, authorities said.
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One of the homes belonged to Flea of the Red Hot Chili Peppers. In a text message to a Times' reporter, the bassist said his home had "burnt to a crisp."

Corral Canyon Fire - The Fire Department reports that the fire is approximately 4,650 acres (25% containment). The fire is expected to be contained by November 27th. There are over 1,700 firefighters, 290 engines, and 19 aircraft on scene.

The Fire Department has confirmed that 79 structures have been damaged or destroyed:

51 structures destroyed (49 single family dwellings, 2 outbuildings)
27 structures damaged (24 single family dwellings, 3 outbuildings)
1 mobile home destroyed
8 vehicles destroyed

Mandatory Evacuations: Corral Canyon on the East, Kanan to the West, Mulholland to the North, PCH to the South

An evacuation center has been set up by the Red Cross at Agoura High School, 28545 Driver Road. A second evacuation center has been set up at Channel Islands High School, 1400 Raiders Way, Oxnard, 805-385-2787.

Road Closures:
- PCH- From Malibu Canyon to Trancas Canyon
- Kanan- PCH to Mulholland
- Latigo Canyon from PCH
- Corral Canyon from PCH

AP photo by Dan Steinberg