FILE — A firefighter uses his bare hand to feel for underground heat while looking for hot spots in an area of brush that burned during the Palisades Fire, in the area of Topanga, Calif., Jan. 13, 2025. Blazes that firefighters thought had died but then later came roaring back to life have become increasingly common, heightening scrutiny of how first-responders put out wildfires. (Max Whittaker/The New York Times)
IN October 1991, a small grass fire was reported near the Caldecott Tunnel in Northern California’s Berkeley Hills.
It seemed minor, but five years of drought had primed the eucalyptus and Monterey pines for disaster.
Firefighters worked through the night to stamp out hot spots and felt lucky it wasn’t windier.
By the next day, their luck ran out.
As a Diablo wind began to howl, embers buried in dry brush came alive. Pine needles ignited and trees exploded, fuelling one of California’s deadliest wildfires.
The so-called Tunnel Fire killed 25 people and destroyed nearly 3,500 homes.
Mark Hoffman, now 71, was an Oakland fire lieutenant at the time. The memory came rushing back recently, after authorities in Los Angeles linked the deadly Palisades fire to remnants of an earlier blaze thought to have been extinguished.
“It was like, ‘Oh no – that again,’” Hoffman said.
These are known as holdover fires, rekindled fires – or, more ominously, zombie fires.
California’s fire culprits are usually familiar: faulty power lines, lightning strikes, arson, careless campers or the homeless trying to stay warm. But some of the state’s most devastating blazes began as fires assumed to be dead – only to roar back hours or days later.
Experts say these rekindled fires are becoming more common as climate change dries out landscapes, fuels megafires and drives stronger, more erratic windstorms.
Under the right conditions, a glowing ember can hide deep in roots or soil for days, even weeks. All it takes is a hot gust of wind to relight it – the same way you blow on a dying campfire.
“Extreme winds can reignite smouldering things that normally wouldn’t reignite,” said David Calkin, a fire management expert and former researcher at the US Forest Service’s Rocky Mountain Research Station in Montana.
The wildfire that erupted on Jan 7 in Pacific Palisades, one of Los Angeles’ wealthiest neighbourhoods, killed 12 people and destroyed more than 6,800 structures – mostly homes.
Federal prosecutors say it began as a holdover from a 3.2ha brush fire intentionally set on New Year’s Day along a hiking trail in the nearby Santa Monica Mountains.
Jonathan Rinderknecht, 29, a former Palisades resident, has pleaded not guilty to setting that original blaze.
Prosecutors say he had a fascination with fire imagery and used a lighter to start the flames. A burning shard of wood reportedly lodged itself in a dry root about 6m from where firefighters were working.
Unseen, that ember lay smouldering underground even as crews returned repeatedly to check for hot spots.
A week later, fierce winds fanned it back to life.
Legal experts say it may be difficult to hold Rinderknecht responsible for the second fire, as the first caused no injuries or property damage. But scientists agree the link is plausible – and not unusual.
The 2023 inferno in Maui, which killed at least 102 people and razed the resort town of Lahaina, was also fuelled by embers from an earlier blaze that reignited.
And in 2022, New Mexico’s largest-ever wildfire – the Calf Canyon/Hermits Peak Fire – began when buried embers from a winter “pile burn” rekindled after three months under snow. That blaze consumed 138,000ha in the southern Sangre de Cristo Mountains.
At first, Calkin doubted claims that the Palisades fire was a holdover from New Year’s Day. Urban fire departments, he noted, tend to mop up thoroughly. But a visit to the trailhead changed his mind.
“The dry chaparral, the wind-scoured slopes, Malibu and Topanga Canyon right next door – it seemed like they’d been dodging a bullet for a while and just got hit with a howitzer,” he said. “A 160kph wind can do anything.”
Los Angeles fire officials insist they had carefully checked the original burn area, “cold-trailing” its perimeter by hand and digging for residual heat.
At a community meeting in mid-January, Assistant Fire Chief Joe Everett told residents: “That fire was dead out.”
He said hose lines were left in place for days. “If investigators find that the Palisades fire arose from old embers,” he added, “it would be a phenomenon.”
But investigators soon determined that was exactly what had happened.
Now, some displaced residents are suing the city and state, claiming officials failed to ensure the fire was fully extinguished.
Plaintiffs argue that crews could have used thermal imaging cameras to detect lingering heat – a charge fire officials reject.
Interim Fire Chief Ronnie Villanueva said such cameras are of limited use in California’s chaparral terrain.
“Holdover fires can be nearly impossible to detect with infrared imaging,” he said. “Smouldering often occurs deep below the surface, especially in chaparral where dense root systems conceal residual heat. Under extreme winds, low humidity and prolonged drought, these fires can reignite despite full suppression efforts.”
Kenny Cooper, the Los Angeles field chief for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said his office found no evidence firefighters could have stopped the later blaze.
“With wildland fires, lightning can hit a tree and get down into the roots, smouldering for days,” he said. “It’s nothing a suppression unit can really prevent.”
In the age of megafires, even the smallest ember can prove catastrophic.
And in California’s drying hills, where the wind never stops blowing, it’s becoming harder to tell when a fire is truly out – and when it’s just waiting to wake up again. — ©2025 The New York Times Company
This article originally appeared in The New York Times
