Firefighters around Los Angeles are making steady progress against large, fast-moving fires that have swept through the city this month. Containment surrounds The Palisades Fire and the Eaton Fire is increasing, but Another explosive fire hazard Stays high in dry conditions and high winds.
There have been fires so far At least 28 people were killedBurned more than 63 square miles and destroyed more than 15,000 homes, offices and shops.
Wildfires are a fact of life in California. They are a natural phenomenon, clearing decaying vegetation, restoring nutrients to the soil and helping new plants to sprout.
But their increasing devastation is the result of human decisions: More homes and businesses built in wildfire-prone areas means more fire is likely to start, and more destruction when one does burn. Suppressing natural fires and not trimming vegetation near structures can mean more fuel is generated. And California’s weather is likely to change as climate changes Larger swings between rainfall and droughtImprove conditions that promote wildfires.
The current fires started after record rainfall, record heat, record dryness, and high winds descended on one of the most populous parts of the country. To track recent wildfires Costliest fire on record. The wildfires will only worsen California’s ongoing housing crisis and could reshape the city’s makeup as wealthy residents are forced to rebuild and impoverished Angelenos. The region will carry these wildfire scars for years. As Vox’s Rachel Cohen wrote, “Recovering what’s been lost — which would take years even after possible accelerated approval — won’t be enough to avert a mounting crisis.”
On the other hand, many human factors are contributing to the increasing destruction from wildfires, meaning that there are some decisions we can make to reduce the damage. And as the flames die down and residents return, the moment presents an opportunity to think more holistically about reducing wildfire risk in Los Angeles and other fire-prone regions.
“There’s a lot we can do as residents and homeowners to really change that trajectory and take small, often inexpensive steps that can make a big difference in changing the outcome when our buildings are exposed to wildfires,” said Yana ValachovichA fire scientist with the University of California Agriculture and Natural Resources Fire Network is studying resilience in the built environment.
I spoke to him just as he was leaving Los Angeles after closely surveying the wildfire damage. He told me that he noticed that the destruction was not just a function of the materials used to build the houses, but how they fit into their surroundings, how they interacted with nature, and the sophistication of the firefighting response.
This conversation has been edited for length and clarity.
Umair Irfan
For people watching the wildfires from afar, one question comes to mind as pictures of the devastation arise: Why are so many homes in Los Angeles made of wood?
Yana Valachovich
From what I saw in both the Eaton and Palisades fires, we were basically seeing houses where the framing might be made of wood, but the outer envelope was basically made of a stucco or stucco-like product. To me, it doesn’t matter if it’s wood or metal, it’s really how it’s designed, materials, installed and maintained. All these elements need to work together. No single product is going to save a home in the face of a fire.
Umair Irfan
So wood is not necessarily a bad choice in fire-prone areas?
Yana Valachovich
I’m a licensed professional forester, so I’ll share my biases on what I do with wood. We grow a lot of trees in California. These are natural resources available to us, and I think it’s important to be able to use what you have in your community. Wood itself is flammable, but there are treatments that can make it fire-resistant.
We also have to think about it from a climate perspective and from a natural resource perspective. The environmental footprint of building with cement is quite high. Making cement takes a lot of energy and we usually have to ship it from somewhere else, which adds to the transportation footprint.
Building materials made from wood are produced in California. Their environmental footprint is small, and through Precautionary forest managementThey can indeed be a very important sustainable resource that can increase the resilience of our forests.
People are really excited about the possibility of reducing fire exposure in large wooden construction and high-rise buildings.
But there are broader questions around what we build with, where we build, how we build. There is no clear winner that checks every box in terms of resilience, environmental impact and sustainability.
Umair Irfan
Is it true that any material can burn at any time?
Yana Valachovich
I just want to backtrack for a second. It’s not just the building and how it’s built; It’s the connection between vegetation and other combustible materials—how they directly touch or surround the building—that makes a substantial difference in fire risk.
There are three types of fire exposure that buildings experience.
One is direct flame exposure, meaning the fire is moving through some type of combustible material. That may be wildland vegetation. It can be planted in plants. It can be dry grass. It can be wood mulch. I think what most people think about, is this wall of fire that just hits the house.
A second component of fire exposure is embers, which are pieces of burning debris. They move around and around a structure and it is quite easy for them to find a path to create new spot fire. For example, you leave the dog door open. There is a gap around the garage. There is an open window, or a window is broken. These are all ways to enter the fire.
We can do things that help harden the structure so that it is less vulnerable to embers. We can upgrade our vents so that the vents are not sized to allow an amber to go in to let something burn.
Then the third component is called radiant heat. Radiant heat is not in direct contact; It is only the heat that is transferred through the air that causes failure in the structure. When you get all that radiant heat, what you see is either the glazing that helps hold the window panes starts to melt, or the heat is so intense that it breaks the glass.
So, it’s a bit more complicated than how a wooden or non-wood exterior building is finished. It has to do with blocking these three pathways. I have seen all three paths lead to fire in the past few days.
Umair Irfan
Can you tell how much the improved building codes had an effect on which houses survived? Were the new homes better under the high standards?
Yana Valachovich
There is some analysis work that needs to be done.
In California, in 2008, we began implementing a specific component of the California Building Code. Section 7A. Its focus is specifically on improving the fire resilience of external components of structures, not internal sprinklers, and not on how to control fires from within. So, since 2008 or so we have a whole new population of buildings in high fire severity areas that are built to a higher standard.
Unfortunately, I didn’t get to see any of the buildings I was out on during my two days, but I’m really looking forward to collecting extensive data to be able to see how they performed overall. This is one of our key questions: Do the codes work? How well do they work? Do they need any other changes?
Umair Irfan
i saw Some viral pictures Individual houses that survived and the rest of the neighborhood were burned There was one in particular that looked paneled with wood. What do you do with that?
Yana Valachovich
I haven’t had a chance to see that building, but by and large this structure implements a lot of what we’re talking about. It has another advantage: it has very shallow eaves. The eaves do not overhang much. Why this is important is that when a spot fire occurs, it starts to generate its own heat and you get an eddy effect, which is similar to a wind circulation pattern. That really puts pressure on Eve’s area. If your under-eye areas are quite shallow, there isn’t much room to expose.
It’s like a short brim hat vs a wide brim hat. A wide brim hat gives you more sun protection, but it also has a lot more area where you can conduct the heat of the fire up and down.
Umair Irfan
Beyond building codes, what is preventing every home from using best practices for fire resilience?
Yana Valachovich
I think it is lack of awareness of people. Also, most people don’t build new homes. They mostly buy from existing housing stock or from someone you know who has put in a subdivision. I think the challenge is actually within the building community and the design community to help them understand.
We now have an opportunity after this fire to become stronger and consolidate the best information available around so that homes are better prepared for this type of exposure.
Umair Irfan
When you were out and about, did you see anything that was surprising or counterintuitive?
Yana Valachovich
There are two things that really surprised me, and I’ve done half a dozen research projects like fire damage cases.
I expect to see more uniformity in amber exposure. Why it’s important I’ve seen many buildings that survived, and what I’ve concluded is that part of the secret to their success is that they just didn’t get as much exposure to the embers, which means the wind didn’t constantly carry the embers everywhere. Micro-topography is what really matters. I think the temptation is going to say, “Oh well, that house had all the right elements and protections,” and I wish I could. What I observed was that there were different types of exposure.
I also noticed that there was more firefighting response than I expected. Based on the media, there is so much talk about lack of availability of water and not having enough resources. But I’ve seen firefighters do a lot of great work and they’ve made an impact on most of the homes I’ve seen survive through both small and large operations.
Umair Irfan
How many small jobs were there?
Yana Valachovich
A smaller one will intercept the fire coming down the neighbors wooden fence and then connecting to the neighbors fence. Many of these houses did not have large distances between one house edge and the next house edge. There will be a gate that closes off the walkway on both sides of the house. So there were people who specially cut down the wooden gates so that the building would not catch fire. Firefighters are going door-to-door breaking those connections. In other places, a little bit of water went a long way to stop the progress.
Firefighting resources were available to start the big thing. I think the responders were moving quickly and efficiently through the neighborhood to help people in those situations. Southern California has more resources than I’ve ever experienced.
