Why some structures have withstood the LA fires

CNN
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Eric Martin, sitting in the hotel room where his family sheltered from the Eaton fire, was certain that his house in Altadena, Calif. — the place he once thought his 1- and 3-year-old sons would know as their childhood home – was gone.

When a friend sent him a picture of the house still standing, he and his wife held each other, stunned, and cried discreetly so as not to alert their boys.

“I couldn’t believe it,” Martin told CNN Monday, his voice breaking. “The fire went so fast. I thought for sure it would be gone. It just didn’t even seem possible that it could still be standing, and there it was.”

Martin returned to the house later that day to find it still there, as were those on either side of it. Almost everything else is gone on his block.

“It’s just ash and bare chimney stacks,” he said.

As many as 12,000 homes, businesses and other structures may have been destroyed in the wildfires raging in Los Angeles County, turning entire communities into ashen piles of rubble.

But here and there amid the Palisades and Eaton fires, in places not protected by the private fire crews of the wealthy, a home survived — a seeming miracle — raising questions about how one structure can make it through while others within for shouting distance burns to earth.

While it may be impossible to ever know for sure, several variables may be at play for the homes that survive, experts say: a smart, fireproof design; an owner’s preparation, such as removing flammable vegetation; the sometimes unknown intervention of the firemen; wind and weather; or quite frankly luck.

“You’ve seen some examples where ‘luck’ isn’t the worst word to describe how some homes survived,” said Janice Coen, a project scientist at the National Center for Atmospheric Research who studies fire behavior.

“But sometimes people just don’t recognize the factors in the physical environment,” she said. “It could be luck, it could be an action they took.”

Design, construction and preparation

It may seem that the survival of a home depends a lot on its construction. And in fact, the California Department of Forestry and Fire Protection is increasingly encouraging homeowners to “harden” their homes by implementing features that help fireproof them.

This can include building or retrofitting key parts of a home – such as the roof, walls, windows, decks, garages, fences and gutters – with more ember and flame resistant materials such as concrete and steel.

Architect Greg Chasen believes a number of these features helped save a home he designed and helped build last year that survived the Palisades Fire: He published on X a photo of the home showing it almost untouched, standing untouched next to its neighbor, now a charred husk with a burned-out vehicle sitting on its frame in the driveway.

Building the home to withstand a wildfire was not a “priority in the design,” Chasen told CNN. But he and the owner had both witnessed these kinds of fires, and they continued with that threat in mind. “Once you see what a wind-driven fire can do, I don’t know — it’s just indelible.”

The architect pointed to features including the home’s walls: fire rated for one hour, meaning a fire could be next to the wall for that long without igniting. The roof was made of non-combustible materials, he said, as was the deck’s finish.

The multi-pane toughened glass windows were also a “huge part of the equation,” Chasen said. The only damage to the home was to two of the exterior panes – one cracked, while the other below it completely shattered. But the interior panes held, Chasen said, preventing sparks from entering the home where the furniture could have ignited the fire.

In California, adding wildfire safety measures beyond building codes can increase construction costs for new homes by 2% to 13%, according to a report from the Insurance Institute for Business and Home Security. Hardening existing homes can vary and likely ranges from $2,000 to $15,000, while full hardening can cost as much as $100,000according to Headwaters Economics, an independent, nonprofit research group.

Chasen also credited the owner for taking steps to prepare the home. Its landscaping was already vacant, the architect said, but as the fire approached, the owner spent hours clearing the lot. For example, he opened a wooden gate attached to the house that could have acted as a “fuse” if the fence caught fire, Chasen said. Garbage and an outdoor grill were also kept away from the home.

This is called creating a “safe space” around the home, Coen said: a buffer zone cleared of combustible materials, like the dry vegetation that has helped exacerbate this round of Southern California fires. Creating this “safe space,” she said, gives a home a higher probability of survival by reducing sources of “radiant heat” directly on a home.

“We tend to think of big fires tearing through the trees,” she said. “But it can often be small fires that sneak up to the home, which is why the safe room is so important.”

The influence of the wind – and pure luck

Firefighters are looking for those elements, Coen noted. And they make decisions about which homes may be more defensible than others and thus worthy of the resources needed to save them.

“Our experience, as firefighters on the ground, we see which homes are able to be saved and which are destroyed,” State Fire Marshal Daniel Berlant told CNN in November, as a different wildfire burned nearly 20,000 acres outside Los Angeles. “The research that we’ve done has really led us to be science-based in the ability to say that if you do these mitigations, your home is significantly more likely to survive a wildfire.”

But there’s often no evidence that a first responder worked to defend a home, said Alexander Maranghides, the senior technical manager of the wildland urban interface group for the National Institute of Standards and Technology, part of the U.S. Department of Commerce.

In fact, figuring out why a home survived may require an in-depth, years-long study and reconstruction of the type Maranghides’ team is conducting, he said, pushing back on the idea of ​​a “miracle home.”

“It’s not a miracle, we just don’t know,” he said. “Was it luck? Was it the wind? Was it the wind and the defensive action? What happened? You can’t say because you don’t know.”

Some homes—not including those protected by expensive private fire crews that often trigger backlashes—survive because a firefighter happened to be well-placed to defend them.

Another factor could be wind direction, which can vary rapidly in both space and time depending on the weather, topography and air temperature, among other variables, said Coen, who works to determine how a fire might spread based on airflow, weather and the winds the fire creates.

“Even in the wild country, away from homes, you’ll see what we call the ‘fire mosaic.’ That is, there will be great variation in the severity of the burn,” she said. “Some areas will be burned completely, but others areas nearby will be untouched and you will have islands of unburnt fuel.”

In an urban environment, “why a (house) survives can be some really local wind effects that you might not be aware of,” Coen said.

As for Martin, whose Altadena home survived, he has no idea why his house is still standing. It is a stucco house – among the fireproof materials. But it’s also surrounded by dry vegetation and bush that hasn’t seen rain in months.

“It just seems,” Martin said, “like pure, dumb luck.”

CNN’s Alaa Elassar contributed to this report.