BRENTWOOD (CBSLA) – The devastating Getty Fire was sparked by a tree branch blown by winds onto a power line belonging to the Los Angeles Department of Water and Power in what is being called an “accidental cause,” city officials said Tuesday.

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Calling it an “act of God,” Los Angeles Mayor Eric Garcetti said dashcam video and photos showed a tree branch falling onto power lines sparking the fire around 1:30 a.m. on Monday.

Investigators used burn patterns, witness statements and physical evidence to determine the cause to be an accidental start, according to LAFD spokeswoman Margaret Stewart.

The fire was likely caused by a tree branch that broke off during the high wind conditions and subsequently landed on nearby power lines, which resulted in sparking and arcing that ignited nearby brush, said Stewart. The power lines remained intact.

There is no evidence of arson or an intentionally set fire and there is no evidence of a homeless encampment in the fire’s area of origin, Stewart added.

During a press conference Tuesday afternoon, Garcetti emphasized “this is not an incident where we saw a failure of equipment”.

On Tuesday morning, Garcetti noted that arson investigators did find a downed power pole in the area, but they determined it was not the cause.

“There’s a separate power pole that was in the media that was absolutely, we concluded, not part of how this started,” Garcetti said. “It was just burned from the bottom, fell over, it’s still intact, the lines are intact.”

The announcement comes as firefighters Tuesday continued to make progress on the wildfire which broke out on the west side of the 405 Freeway in the Sepulveda Pass early Monday morning and has so far scorched 658 acres and destroyed several homes, with mandatory evacuation orders set to remain in place for thousands of people as more powerful Santa Ana winds are slated to hit the region.

A firefighter walks past houses burned by the Getty Fire on Oct. 28, 2019. (Getty Images)

The Getty Fire was 15 percent contained as of Tuesday evening. Twelve homes have been destroyed and another five damaged.

An extreme red flag warning which took effect at 11 p.m. Tuesday remains in place through 6 p.m. Thursday due to yet another Santa Ana wind event which has hit the region. The National Weather Service predicts this could be the strongest Santa Ana event the Southland has seen this season.

“Tonight at about 11 p.m. we will see some very strong winds,” Garcetti said at a Tuesday morning news briefing. “To some degree, those will be countered by a little bit more moisture in the air. But that moisture will drop down dramatically tomorrow morning. So people will not be returning to their homes this evening.”

“We’re very concerned about tonight’s wind event,” L.A. Fire Department Chief Ralph Terrazas reiterated.

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An evacuation map for the Getty Fire. Oct. 29, 2019. (Los Angeles Fire Department)

As of Tuesday morning, the mandatory evacuations remained in place for the area bordered by Temescal Canyon Road to the west, Sunset Boulevard to the south, Mulholland Drive to the north and the 405 Freeway to the east.

Approximately 7,091 residences were in the mandatory evacuation area.

The area bordered by Topanga Canyon to the west, Sunset Boulevard to the south, Mulholland Drive to the north, Mulholland Drive to the north and Temescal Canyon Road to the east was under a voluntary evacuation.

That also included the Mountaingate community, where mandatory evacuations were lifted Monday evening.

The fire forced the closure of the southbound 405 Freeway between the 101 Freeway and Sunset Boulevard for 10 hours. It reopened just after 7 p.m. Monday. However, all southbound and northbound off-ramps between Mulholland Drive and Sunset Boulevard remained closed Tuesday.

The Getty Center and the Getty Villa museums will stay closed through Friday. Neither facility is considered at immediate risk, but fire crews and other emergency responders have used the Getty Center as a response hub, according to authorities.

The NWS reported Tuesday that wind gusts could reach up to 80 miles per hour during the upcoming Santa Ana wind event.

A firefighters sprays water on a home as firefighters battle the Getty Fire in Brentwood on Oct. 28, 2019. (Getty Images)

Meanwhile, firefighters were trying to expand containment lines around the Getty Fire and ensure it doesn’t flare up and spread. There were no reports of any injuries so far. At least 1,100 firefighters from multiple agencies were assigned to the blaze, along with multiple water-dropping helicopters and air tankers.

Among those evacuated were L.A. Lakers star LeBron James and former Calif. Gov. Arnold Schwarzenegger, whose Hollywood premiere of his new movie “”Terminator: Dark Fate,” was canceled because of the fire.

The Santa Monica-Malibu Unified School District reopened its schools Tuesday after closing them all Monday. About 15 schools in the Los Angeles Unified School District remained closed Tuesday. The Chalon campus for Mount Saint Mary’s University, which was forced to evacuate all its students, remained closed. UCLA resumed classes Tuesday after canceling them Monday.

Evacuation centers were open Tuesday at the Westwood Recreation Center and the Palisades Recreation Center.

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