As Los Angeles reels from the staggering toll of fires, one question has profound economic, financial and political implications: What started the fires?

The Palisades and Eaton fires have destroyed more than 12,000 structures and are expected to be the costliest fires in U.S. history, with losses estimated at $50 billion to $150 billion.

Residents were swapping accounts of what they saw in the surrounding hills before the fire. The utility company is investigating the fault near its equipment. Politicians pointed fingers. Online detectives are sharing videos and other alleged evidence on social media platforms.

A week ago on New Year's Day, a small fire broke out near the site of the Palisades Fire. Can old embers be rekindled? Before the Eaton Fire, it appeared the burned home still had power amid high winds. Was it caused by downed power lines? A "person of interest" has been identified in the Kenneth Fire. Was the fire the work of an arsonist?

So far, officials have been extremely cautious and cautious. They don't have solid answers yet, but they say they will if they can complete the complex and often months-long "origins and causes" investigations that are only now beginning.

"There's a lot of misinformation circulating and a lot of people want answers -- and understandably so. We're going to provide those answers," said Ginger, a spokesperson for the Bureau of Alcohol, Tobacco, Firearms and Explosives, which is investigating the cause of the Palisades fire. Ginger Colbrun said. "But we have to get more people here to investigate."

Kolbrun said ATF's National Response Team, one of the nation's most prominent large-scale disaster investigation units, is handling the Palisades fire and will get to the bottom of it. But with fires still burning, burning patterns changing and new evacuation orders still being issued, investigators still need time to gather the facts.

"Any conclusion at this point is speculation," she said. She could not provide a timetable for when the investigation would be concluded.

The same goes for other investigations in the region led by other city, county and state agencies with fire investigation expertise, who are sharing the workload with the ATF given the number of fires and complexity of the effort.

Investigations into the causes of fires as large and intense as the Los Angeles fire often take months or longer. For example, after a massive wildfire killed more than 100 people on Maui in August 2023, the ATF National Response Team took more than a year to investigate and did not release official findings on the cause of the fire until October 2024. .

Experts say the causes of wildfires, including those sweeping through urban areas, can be extremely difficult to investigate — for obvious reasons, including the intensity and temperature of blazes so large they destroy nearly everything in their path.

“You’re basically throwing a crime scene into the oven,” said Michael Wara, director of Stanford University’s Climate and Energy Policy Program and a former California wildfire commissioner.

However, he said, the science behind fire investigation has become very advanced and technical, and in urban settings there is a wealth of data available to draw on, including from utility companies.

Vara said finding the cause of these fires is critical because the information could help Los Angeles and other cities avoid similar fires in the future. But by the same token, coming to the right conclusion is more important than rushing to an answer, he said.

"We need to respect the process and let the process work," he said. “We also want to work to ensure that this process is complete and complete.”

Vara said one thing to remember about these types of fires is that there doesn't necessarily have to be a single origin or cause. Sometimes large fires have multiple origins, especially in weather like the one Los Angeles has been experiencing recently, with Santa Ana winds blowing at unusually high speeds.

Vara said one of the main questions he faces concerns utility decisions by Southern California Edison and the Los Angeles Department of Water and Power to either shut down lines or keep power on during high winds.

He said SCE had said it had cut off the power, but that was problematic. LADWP typically does not cut power, relying instead on its efforts to stabilize and strengthen lines, including mounting them on steel poles rather than wooden poles.

He said a major concern with last week's high winds was "blow-in," or material such as tree branches that can fly through the air and even hit power lines from a distance, even if the power lines are immediately relieved and the area is well maintained by the utility. and clean up.

Vara said an investigation into the cause of the fire could include collecting data from the utility, including from individual homeowners' electric meters, about what was happening on the grid in the early days of the fire.

He said if LADWP lines do cause the Palisades fire, the city could pay a high financial cost. Private utilities found at fault in past fires have been forced to pay billions of dollars to victims. Some of the damage could be paid for by the state's wildfire fund.

Former state Sen. Dean Florez, a member of the California Air Resources Board, said that while some potential ignition sources are currently being investigated, "if history is any indication, power lines remain the primary focus."

"Past experience tells us that utility equipment is the primary cause of California's deadliest wildfires. This historical pattern cannot be ignored when discussing prevention measures," Flores said. "The real question here is not just how these fires occur, but how they can be prevented."

He said the state, through the California Public Utilities Commission (CPUC), has weakened its wildfire prevention strategy by reducing funding for underground transmission line projects, which he said is a proven long-term solution to reducing wildfire risk.

"Yes, the cost of underground work is $3 (0 to) $4 million per mile, but that pales in comparison to the catastrophic cost of the devastating Los Angeles County wildfires," Flores said. The losses to investors could easily exceed $500 billion.”

He said he believed the CPUC was inadvertently allowing these risks to persist "by favoring less costly and less effective strategies such as insulated wires and vegetation management while deprioritizing underground work."

Flores said utilities such as Southern California Edison and PG&E have made progress in reducing fire risks by placing some transmission lines underground, with significant declines in utility-ignited fires reported in high-risk areas. But he said CPUC funding cuts have forced utilities to scale back those efforts, putting even SCE's modest plan to bury 100 miles of wires underground this year at risk.

In recent days, investigators appear to have focused in part on the area around a burning transmission tower in Eaton Canyon, with officials acknowledging their work as part of the investigation into the cause of the Eaton fire. Edison said it found no evidence that its electrical equipment caused the fire.

Another theory that has emerged recently about the Palisades fire is that a fire in the area started a week ago by early New Year's Day fireworks was reignited by high winds, even though the Los Angeles Fire Department had previously stamped it out.

Kolbrun said the connection is speculative at this point, but investigators will consider all possible causes of the fire.

Sources familiar with the investigation told The Times that officials are aware of the earlier fires, generally near where the Palisades fire started, and are investigating whether they are related. People are known to hang out in the area and sources said someone may have started another fire at the same location on Tuesday.

Walla says such an origin is possible. He cited the example of the massive Calf Canyon fire in New Mexico's Hermit Peak, which started after the remnants of a U.S. Forest Service-mandated burn reignited. The 1991 Oakland Hills Fire also started after a smaller fire failed to be completely extinguished.

It's also possible that the Palisades fire was caused by multiple causes at the same time, Vara said. He pointed to the example of the Marshall Fire in Boulder, Colorado, which was caused by damaged power lines and embers from a trash fire a week earlier.

"There may have been multiple fires occurring at approximately the same time and location," Vara said.

Vara said it's impossible to draw any conclusions about the cause of the Los Angeles fires until more evidence is collected. But he said it's important to get the right answers.

"We need to learn from these urban fire storms," ​​Vara said, "so we can find ways to avoid similar events from happening again."

Los Angeles Times reporter Richard Winton contributed to this article.