© 2024 Milwaukee Public Media is a service of UW-Milwaukee's College of Letters & Science
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

To Prevent Wildfire Devastation, Researcher Looks At Building Design


The wildfires in Northern California are nearly contained, but close to 500 people are still missing. In recent weeks, it's become increasingly clear that there's no stopping some wildfires. They're too big and too fast-moving for firefighters to contain. But containing wildfires is not the only way to battle the devastation caused by them. Reporter Stephanie Joyce has this story about one man's efforts to show there's another way.

STEPHANIE JOYCE: This story begins right around this time of year in 1980. It was Santa Ana season in Southern California - the time of year when the so-called devil winds blow down from the mountains hot and dry, creating dangerous fire conditions. On the Monday morning before Thanksgiving in the hills just east of San Bernardino, an arsonist lit a fire that quickly made its way to the city as 911 fielded calls from panicked residents.


UNIDENTIFIED PERSON #1: Fire approaching my house at (unintelligible).

UNIDENTIFIED PERSON #2: OK, ma'am. I want you to just get out of there.

JOYCE: By the end of the day, the Panorama Fire had destroyed more than 400 homes and killed four people. At the time, it was one of the worst fire disasters in California history. The devastation caught the attention of a young Forest Service researcher named Jack Cohen. Forty years later, he still chokes up when he thinks back on how overwhelmed the firefighters were that day.

JACK COHEN: It was pretty emotional, particularly listening to the radio traffic.

JOYCE: Desperation was what he heard. Why did the Panorama Fire destroy so many houses? Jack started to poke around, and it didn't take long to uncover the answer.

COHEN: As it turns out, every house had a flammable wood roof.

JOYCE: Around the burned homes, there were green trees.

COHEN: People think that if that kind of destruction occurs, there must be this tsunami of flame that rolls through the community.

JOYCE: But that's not how fire works. What had actually set the homes on fire were embers, chunks of burning material lofted in front of the fire by strong winds.

COHEN: Following that, I started seeing roughly the same kind of pattern developing over and over and over again.

JOYCE: He saw that the houses were burning - not the trees. And Jack found himself wondering if the emphasis on fighting fires was misplaced and if instead, we should be thinking more about how to design homes to survive fires. Jack wasn't the first person to think about that, but he was the first to do extensive research into how houses burn in wildfires. The first thing he wanted to know - how close do the flames of a wildfire have to be to a house to catch it on fire? To answer that question, he did a series of experiments, including one in the late 1990s in Northern Canada, where he set an actual forest on fire.

So you actually, like, cut plots into a forest...

COHEN: The boreal forest.

JOYCE: ...And then set them on fire...


JOYCE: ...And watched them burn.


JOYCE: What Jack found in the experiment was that an entire forest could be on fire 30 feet away from the house and nothing. It was fine. In other experiments, he looked at how embers if allowed to smolder could quickly turn into fires that consumed entire houses. He began to develop guidelines for designing and landscaping properties to withstand a wildfire. And he started by drawing a buffer.

COHEN: The home ignition zone is limited to the house and its immediate surroundings out to about 100 feet.

JOYCE: Between 100 feet and 30 feet from the house, he recommended spaced trees so that the fire can't jump between them and is forced to the ground. Between 30 and five feet, landscape and design so the ground fire loses steam. And, within five feet of the house, stop the fire dead in its tracks with things like rock beds and well-irrigated grass.

COHEN: You don't have to live in a bunker. You don't have to cut all your trees down.

JOYCE: Jack's experiments showed that the main factor in whether a house was going to burn wasn't the intensity of the wildfire or its size. It was really about what was happening within 100 feet of your home. But even though Jack's ideas are simple and compelling, they aren't as widely adopted as he would like them to be.

COHEN: One of the very frustrating things that I had experienced this past summer, particularly from the California fires, is the continued sense of fatalism. Oh, well, there's nothing that could be done. Well, no. The bottom line is that we can do something. It just doesn't have anything to do with controlling the wildfire.

JOYCE: Last year, the federal government spent more than $2 billion fighting fires and just a small fraction of that on prevention and mitigation efforts. But when communities put the principles Jack articulated into practice, they help. There are neighborhoods in Southern California built with wildfires in mind that have survived when nearby homes didn't. But it can be expensive to make the changes that are necessary and hard to enforce rules community-wide about vegetation clearing and home design. Jack tells the story about a friend of his who said that modifying homes to make them fire resistant isn't rocket science.

COHEN: And I said to him, no. This is much harder. This is social science. And his comment is, oh, geez. We're screwed.

JOYCE: Watching news footage from the California fires, something stands out if you've spent a lot of time with Jack. Once you get over the shock and horror of seeing neighborhoods reduced to ashes, your eyes shift to something else - the green trees surrounding the burned-out homes.

For NPR News, I'm Stephanie Joyce.

MARTIN: This story was adapted from an episode of the podcast 99% Invisible, which you can find at 99pi.org. Transcript provided by NPR, Copyright NPR.