Los Angeles. Investigators are examining several potential ignition sources for the devastating wildfires that have claimed at least 10 lives and destroyed thousands of homes and businesses in the Los Angeles area.

In Pacific Palisades, a hilly and upscale neighborhood home to Hollywood stars like Jamie Lee Curtis and Billy Crystal, officials have pinpointed the origin of the wind-driven blaze behind a home on Piedra Morada Drive, which overlooks a densely wooded arroyo.

While lightning is the most common cause of wildfires in the US, according to the National Fire Protection Association, it was quickly ruled out in this case. No lightning activity was reported in the Palisades area or near the terrain of the Eaton Fire, which began in east Los Angeles County and has destroyed hundreds of homes.

The next two leading causes under investigation are arson and utility line sparks.

John Lentini, a Florida-based fire expert and owner of Scientific Fire Analysis, emphasized that even large wildfires start small. "This was once a small fire," Lentini said. "Investigators will focus on the origin, analyze it, and determine the cause."

Thus far, there is no official indication of arson or evidence linking utility lines to either blaze. However, California utilities are required to report "electric incidents potentially associated with a wildfire" to the California Public Utilities Commission (CPUC). The commission's staff then investigates whether state law violations occurred, said Terrie Prosper, CPUC’s communications director.

Investigators found that the 2017 Thomas Fire—one of the largest in state history—was sparked by Southern California Edison power lines that came into contact during high winds. That fire claimed two lives, burned more than 440 square miles (1,140 square kilometers), and destroyed hundreds of structures. As of Thursday, no similar reports for the current fires have been posted to the CPUC’s website.

In addition to lightning, arson, and utility lines, wildfires can also be caused by debris burning, fireworks, or accidents.

In one high-profile case in 2021, a couple's gender reveal stunt sparked a fire that burned nearly 36 square miles (90 square kilometers), destroyed five homes and 15 other buildings, and resulted in the death of firefighter Charlie Morton.

As of Thursday, the Eaton and Palisades fires were still raging with minimal containment. Although winds had softened, there was no rain in the forecast, leaving the flames to tear through the dry, expansive landscape.

"It’s going to go out when it runs out of fuel or when the weather changes," Lentini said. "They’re not going to put that thing out until it’s ready to go out."