Media Briefings

Wildfire resilience: buildings, water, and land use

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Last month, more than 5,000 wildfires burned more than two million acres of land in the United States—a new record. SciLine’s media briefing focused on steps communities are taking to gird themselves against wildfires that are generally trending larger, more intense, and more damaging due to climate change. Panelists presented research on efforts to: boost the structural resilience of buildings such as schools and hospitals; protect critical drinking water infrastructure; and adapt land and resource uses to enhance recoverability after a fire.

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RICK WEISS: Hi, everyone. I am SciLine’s director, Rick Weiss, and I want to welcome you to SciLine’s media briefing on wildfire resilience with a focus on buildings, water and land use. This is a topic that’s, of course, important because wildfires are becoming such a big issue with climate change these days but also a topic I have to say I find especially interesting, I think because it calls for solutions that bridge the two fields of science and engineering. And I’m really glad that we have experts today from both of those communities to help us out. A few quick introductory remarks—for those not familiar with us, SciLine is a philanthropically funded, editorially independent, free service for journalists and scientists based at the nonprofit American Association for the Advancement of Science. Our mission is to make it easier for reporters like you to get more scientifically validated evidence into your stories. And that means not just stories that are about science but really any story that can be strengthened with some science, which, in our view, is just about any story you can think of. Among other things, we offer a free matching service that helps connect you directly to scientists who are both deeply knowledgeable in their field and are excellent communicators. We do that for you on deadline. Just go to, click on I need an expert, and while you’re there, check out our other helpful reporting resources.

A few quick logistical points—we’re going to have three panelists today who will make short presentations of just five or six minutes each before we open things up for Q&A. To enter a question during or after the presentation, just hover over the bottom of your Zoom window, select Q&A and enter your name and news outlet and your question. If you want to pose that question to a specific panelist, be sure to note that. A full video of this briefing should be available on our website, maybe by the end of the day or at least tomorrow morning, and a timestamped transcript within another day or so after that. If you would like a raw copy of this recording immediately after the briefing itself, just submit a request with your name and email in the Q&A box, and we’ll send you a link to the video by the end of the day. You can also use the Q&A box to alert us to any technical problems.

OK, to get started, I’m not going to give full introductions to our speakers. Their bios are on the website. I just want to tell you that we will hear first from Dr. Kimi Barrett, who is the lead wildfire research and policy analyst at Headwaters Economics, where she’s led research studying the true cost of wildfires beyond the fires themselves, such as costs of constructing wildfire-resistant homes and enhancing land use planning. She’ll describe some of the unique challenges that wildfire-prone communities face and talk about some land use planning tools that can help make communities more fire-resilient, which may be relevant to some of the communities that you are all reporting from. Next, we’ll hear from Dr. Erica Fischer, who is an assistant professor of civil and construction engineering at Oregon State University, where she conducts research on how to increase community resilience and sustainability during and after disasters. She’ll focus on all the ways that damage to a community’s infrastructure ends up impacting the recovery process and strategies for increasing structural fire resilience of infrastructure and homes. And third, we’ll hear from Dr. Fernando Rosario-Ortiz, who is a professor of environmental engineering and the associate dean for faculty advancement for the College of Engineering and Applied Sciences at the University of Colorado at Boulder. His research focuses on environmental chemistry and how, you know, when you realize that wildfires don’t just burn trees, but also houses and appliances and all kinds of other toxic materials, how wildfires can impact water quality in watersheds and local water supplies and ways that utilities in fire prone areas can best adapt to address these disruptions in water quality. OK. With that, let’s just move ahead to some short presentations—and over to you first, Dr. Barrett.

Challenges for wildfire-prone communities


KIMIKO BARRETT: All right. Thank you very much for that, Rick. Let me go ahead and pull up my presentation. Can I get a thumbs up that you are all seeing this? Do you—yeah. Great. Wonderful. All right. Well, thank you so much for that introduction, Rick. My name is Kimi Barrett, and I’m the lead wildfire researcher and policy analyst at Headwaters Economics. And at Headwaters Economics, we surface and interpret data to inform research, policy and locally driven solutions to help people and communities thrive in a rapidly changing world—in a world, at least in my line of work and with my fellow co-presenters, that is increasingly on fire.

So, let’s talk about fire. Let’s talk about wildfires, to be precise. What’s going on with them? Well, they are in general, just getting much, much worse. Trends indicate that wildfires are increasing with respect to duration, severity and frequency, meaning that they’re a lot longer, they’re bigger, they’re hotter, they’re more frequent, they’re more damaging, and they’re costlier than ever before. And just one indication of this—we know that the wildfire season, or the period of time with which wildfires are most likely to occur, has been extended by about 84 days or roughly three months. But that’s just one indicator of increasing wildfire behavior. Very, very importantly and concurrent with this is that we have more and more homes being placed in wildfire-prone areas, also known as the wildland urban interface, or the WUI. In fact, the WUI is the fastest growing land use type in the lower 48 states, outpacing all other forms of development, with more than one in three homes now located in these wildfire-prone landscapes. As a result of this, we have a lot more structures being burned from wildfires. So, since 2005, we’ve lost 120,000 homes and buildings to wildfires. And unfortunately, almost two-thirds of these have been located in the state of California alone.

And with all of these concurrently rising trends, we’re spending a lot of money at the federal level on suppression. By suppression, I’m talking about the costs spent for firefighters to come in and contain and extinguish a wildfire. So, currently, at the federal level, through the land management agencies and primarily the U.S. Forest Service, we’re spending $65 million per wildfire, which is doubling the cost since 1995 or 1999. Let me repeat that, though—$65 million per wildfire. As of this morning, there has been 40,000 active wildfires in this year alone, and the season is not over. So, my point with this is not that wildfire suppression is costing too much. It’s more that we’re not spending enough on the upfront mitigation and preparation so that communities are better anticipatory and planning for these events before they occur. And it should be noted that with all these numbers, this is what we can actually capture and quantify, but the real impacts to people and communities and families goes much, much deeper than this—that long-standing institutional, cultural, political and economic barriers influence the ability for people to prepare for, respond to and recover from a wildfire.

So, this graphic tries to tease out some of these numbers in terms of impacted people and households that are adversely at risk and disproportionately exposed to wildfires. So, families and households living in poverty, for example, may not have adequate housing or have diminished ability to evacuate or relocate from a wildfire, or they may not have homeowner’s insurance. Health conditions, which are strongly linked to age, race and income, can be adversely impacted by wildfire, smoke and environmental stress. And language, cultural and institutional barriers can influence and make it more difficult to apply for recovery aid, to receive outreach materials for evacuation and planning and communicate other very, very important materials. Additionally, centuries of systemic racism can make it more difficult to trust the institutions and agencies offering these services. And with all of these increasing trends, the wildfire crisis is likely to get much, much worse in the future.

However, I want to assure all of you in this audience that we do indeed know how to do things much, much better. We know how to reduce risks to homes and neighborhoods and, in effect, create communities better adapted to increasing wildfire risks. What I’m talking about is envisioning a community growing alongside inevitable increasing risk—in other words, anticipating a wildfire before it occurs and integrating mitigation strategies into the development framework. It’s planning measures like requiring wildfire-resistant construction materials, retrofitting the existing fleet of vulnerable houses out there and that improving neighborhood design and infrastructure protection so that people and homes, again, are better prepared before a wildfire occurs. This has to happen and be very coordinated at multiple scales. So, at the federal level, it’s examples like hazardous fuels reduction that breaks up fuel continuity in and around a community. At the state level, it’s policies like building codes or vegetation management resources codes that explicitly incorporate wildfire risk mitigation into that planning process. At the local, county and jurisdictional level, it’s things like zoning ordinances, subdivision design standards and open space initiatives that, again, envision how this community is going to grow alongside these increasing risks. And all of this is heavily supported and subsidized by funding at the state and federal level.

An example of what I’m talking about here is in Portola Valley, California. They recently supplemented the statewide building code with a home hardening ordinance that requires all new development in high-hazard areas incorporate the highest wildfire resistant construction materials into the home itself. Similarly, in Summit County, Colorado, they passed an ordinance that prevents—fencing material from the house outwards for the first 10 feet be made with non-combustible material so that the fence can’t act like a wick, effectively leading fire directly to the home itself. Similarly, they have a ban on all flammable materials on the deck, like firewood or a propane tank, during high wildfire seasons. So, these are just a couple examples of what’s being done at the county scale to address these increasing risks.

We also know that if our ultimate goal is to reduce risk to communities and neighborhoods, then we must intentionally and deliberately invest in communities by providing support, technical assistance and resources to increase capacity at the local scale so that wildfire planning and preparation can occur before wildfire strikes and not done as a reactive, post-disaster afterthought. Because these wildfire impacts, these realities that I’m talking to you today about in this webinar, are being experienced, felt and responded to at the community level. And it’s the communities that are stepping up to take action needed to address long-term resilience against these increasing wildfire risks. And I’m happy to talk more about any of this during the follow-up Q&A, as well as my contact information.


RICK WEISS: Fantastic, great overview introduction, terrifying numbers about what’s coming. But actually, it’s super interesting to see that, locally, there is the opportunity to make changes in a positive way. That’s really interesting. Let’s move on to Dr. Fischer.

Wildfire impacts to infrastructure


ERICA FISCHER: Great. Thank you. Thank you, Rick. And thank you so much, Kimi, for that information. And hopefully, I can build upon that. So, I’m going to be talking for the next 6 minutes or so about wildfire impacts to our infrastructure. And so when we’re talking about wildfire impacts to our communities and when—you know, as Kimi so eloquently told us, and all the numbers associated with that, fires are a natural occurrence within the landscape. Much of our landscape actually needs wildfire to continue to occur in order to prosper. So, if we stop to think, why are we—when is it a disaster? Why do we call it a disaster when it does encroach on communities? It really has to do with this loss of functionality of our communities. And we’ve looked at our communities after other disasters and looked at loss of functionality of our communities with respect to health care, education, water, electricity, housing—for earthquakes, for hurricanes, for tsunamis. And we’ve been doing this for decades.

So, we really do understand how our communities function and how all these institutions work within our communities and play a role in the recovery of our communities. Now we’re just looking at it through the lens of wildfires. And one of the reasons we’re focusing so much on housing and those amazing examples in California and Colorado that can be mentioned is because wildfire is one of the only hazards where the burning of homes itself intensifies the hazard. We don’t see that in these other hazards I mentioned before. We’re really seeing that if our homes do catch fire, the homes themselves are going to burn for much longer than the vegetation will burn and create firebrands or embers that can travel up to a mile and a half to five miles and ignite other parts of the community that aren’t near the fire front. So, the combustion of our homes creates this massive additional hazard and intensifies this wildfire in ways that we’ve never seen, really, homes act in a community in these other hazards itself.

But if we focus on our more critical—you know, some of our critical infrastructure, like hospitals and schools, it’s not just the burning of the structures themselves that is the loss to the community. These institutions play roles within that community that are very critical to recovery. Often, as in the case of Paradise, California, they are the largest employers in the town. So, when you have the loss of 90% of the housing stock within your town, who is the hospital actually serving within the town then? And conversely, if you lose your hospital and it is the largest employer in the town, what jobs are you losing for that town itself to sustain the recovery within that town? So, we have to—we really know how—the roles these institutions play within the community. But thinking about, you know, why are we protecting our homes so much? It’s because we really don’t want to intensify the hazard itself. We want to protect these institutions within the town so that the town can recover and we can have health care institutions within the town, educational institutions. We can have a tax base. And we can have people to serve the community.

But in addition, we’re seeing that, you know, once one home combusts and once one home catches fire, the fire spread throughout the community can be quite rapid. I mentioned embers or firebrands before, but also just home-to-home ignition. We often see these clusters of burnt homes because once one home starts, the fire starts in one home, it can quickly spread to these other homes. And so if your home is near another home that’s burning, the risk of your home igniting shoots up. It definitely increases. And this is an aerial image from drones that we flew over the Marshall fire perimeter in—back in January. But also, what we’re seeing when homes burn—and Fernando will talk about this right after me—is when a home is burning, it’s burning for multiple hours. It’s heating up the ground below it. And what’s in that ground below it is this service water line. It’s attaching from the house itself to the main water line.

And often, especially on the West Coast of the United States, this water line is made out of plastic. It’s made of plastic because it has great ductility in earthquakes. And it’s very durable. And what happens when it heats up is—what we’re seeing is it starts leaching volatile organic compounds, such as benzene, which is a carcinogen. And now, all of a sudden, we have contamination within our water distribution system. What also happens is because we are almost maxing out our water distribution system during the fire for fire suppression circumstances, we will have a depressurization of the water distribution system. And ash and soot that’s in the air will get sucked into that service line when the home burns down. That ash and soot also contains contaminants, such as benzene, that will travel throughout the water distribution system. And what these two photos on the top right are melted parts of the water distribution system. But what ends up happening is the restaurants that want to reopen afterwards or businesses that want to reopen after the fire don’t have access to clean water. So, they end up having to use lots of plastic water bottles. And this is a photo taken outside of a restaurant in Paradise, California, after they dealt with their own water distribution system contamination. And we’ve seen this event happen in 15 water distribution systems throughout Oregon, as well. But what we’ve been finding is that this is actually contributing—and this actually contributed to density of damaged homes. So, going back to protecting our homes, the higher density of damaged homes we have, the higher the probability of this contamination during a wildfire. So, I will pass it along, and I want to thank you very much. And additional references will be distributed to all of you.


RICK WEISS: Great. And, yeah, a reminder to reporters, all these slides will be available soon after the briefing for you to look at more closely. Over to you, Dr. Rosario-Ortiz.

Impact of wildfires on water quality and treatment


FERNANDO ROSARIO-ORTIZ: Thank you very much, Rick. Let me start the presentation mode here. And thanks to the previous two presenters for setting the stage. What I would like to do is to talk about from—mostly from the water quality and water treatment perspective, which is a consideration that is very important not only in areas where, as Erica mentioned, you have the devastating impacts of wildfires but also in areas that might be far away or areas—or sometime later when you start to see mobilization of assets and concerns with drinking water production. So, the background related to drinking water is about two-thirds of the municipalities in the U.S. are going to draw water from forested watersheds. These are the same areas that are prone to fires, and these fires can abruptly and adversely impact these watersheds, and the effects can be quite complex and long-lasting. In some cases, we have evidence of impacts of wildfires in our drinking water watersheds going beyond 5 to 10 years.

I like showing this map—comparison of, for example, the extent of wildfires in the summer 2021. As Dr. Barrett mentioned, we’ve had—we’ve been having more and more fires on a yearly basis. And this is how the situation looked by the end of the summer last year. And to the right, you see a map from the U.S. Forest Service forest-to-faucet map, which essentially showcases the same areas where you have—are seeing these fires, which are the forested areas, are the areas that are also considered as sources of good-quality water for production of potable water. Therefore, we see an—obviously, an overlap in these areas and therefore a concern for potable water production.

Over the last many years, we’ve been looking at this—at the effects of wildfires and water quality. We start looking at, obviously, the effects of combustion on the actual watershed, the stabilization of slopes, production of materials, ashes, that can be then mobilized. Then what we see is once you have—you start having the rain events, immediately after the fire, for example, or afterwards you start to see the mobilization of this material that eventually will make it into rivers and reservoirs. And those are the same rivers and reservoirs that are used for production of potable water. From the drinking water perspective, what we see is changes in water chemistry related to changes in the amount of compounds that we see in the water and the amount of particles that we see. Specifically, some of the water—impacts on water resources—number one that we are concerned about is turbidity. I’m showing a picture here on what we do. It’s called a jar test when we test the turbidity removal. On the left, you see water that is fairly clear. That’s what you typically want to treat. On the right is a simulated wildfire-impacted water where you see a higher level of turbidity. And turbidity needs to be addressed by the drinking water infrastructure in order to provide safe water to the (inaudible). We also observe increased concentration of nutrients, metals and organic carbon. Most of these compounds are typically present in the water at low enough concentrations, but at high enough concentrations, they can impact water—potable water production. Nutrients, for example, going into a reservoir can lead to algae growth, and metals and organic—and metals can result in potentially higher levels of toxic metals. And organic carbon can then impact the formation disinfection byproducts, which are compounds that are regulated by the U.S. EPA and are formed during the disinfection process. And we also see impact on treatment operations, including impacts to infrastructure. We’ve all seen pictures of the aftermath of a wildfire after a rain event where you see massive mobilization of sediments that can impact roads and can also impact other infrastructure.

As mentioned before, we started to see more issues with WUI fires. Dr. Barrett mentioned this. There’s been very famous cases in California in 2018 that impacted the cities of Paradise, for example. Here are pictures of sampling that occur right after the Marshall Fire in Colorado. And I—that was a significant event that occurred on December 30 when we had high winds, and this has eventually resulted in the combustion of a thousand homes. As Dr. Fischer also mentioned, what happens is, you know, when you have combustion of a—in a wildland area, you’re combusting trees, which are more than likely lower density of fuels compared to a community. When you burn homes, you start to see a burning not only the outside of the house, which might be mostly wood, but also the material observed that we have in the shingles and in other materials, but also the inside of the house. We’re now talking about TVs and refrigerators and dishwashers and all of that, and we are starting to be more and more concerned with contamination after these events. Dr. Fischer referred to contamination to drinking water distribution systems when you effectively have negative pressure events that will either suck in ashes or other materials from the fire that will then be lodged in the distribution system and act as sources of contamination. But we can also observe this contamination is just the runoff from the burn area.

In the case of the Marshall Fire—you see here some of my colleague’s sampling—you may notice the snow. You know, the fire happened one day. The next day, we had a significant snow event. Once you have that melting of the snow, we’ve been sampling some of the surface waters, and you start to see compounds such as benzene that were mentioned by Dr. Fischer. But we also see quite a few other compounds. I’m showing here benzoic acid derivatives. We’ve done work where we’ve quantified up to 14 different compounds that we see. We are aware that we’re going to find one or 200 more compounds at least that are going to be in concentrations that might be high enough. A lot of these compounds, we’re not expecting to be toxic, but it points to the complexity of the issue and how we need to do more work associated with it. We also have fine metals in organic compounds, such as arsenic and zinc, that have been found in situations—runoff situations like this and also in other conditions. And with that, I’ll thank you for your attention. And as Dr. Fischer mentioned, I’ll provide the slides with all the reference work in them.


What is being done well in press coverage of these issues, and where is there room for improvement?


RICK WEISS: Very, very interesting introductory remarks. I think there’s more obviously going on when these wildfires happen than a lot of people think about, so this is going to be very interesting and something that communities need to be addressing and that reportage about seems to be important now. Let’s just get started with the Q&A. A reminder to folks—if you have a question, you can click on that Q&A icon at the bottom of your Zoom screen and let us know your name and outlet. Meanwhile, we usually start these briefings with one question from the moderator, so I want to throw that out now, which is just to ask the three speakers here each candidly to talk about what their reactions have been to news coverage of wildfire issues generally. Is there any advice that you would give—either on the positive side, some kudos for things you see doing well, or some helpful advice for mistakes or perspectives that you think have not been helpful as reporters have gone about covering this? And I’ll start with you, Kimi.


KIMIKO BARRETT: Yeah, great question. And I have three main kind of points, takeaways I want to leave with—well, I’ll start and probably leave with. One—I think Erica said it so elegantly—is that wildfires are an ecological, natural hazard. They’re a process with which our landscapes have adapted to over millennia, and so they are supposed to be there. It’s only when a—you know, a home is placed in harm’s way that they actually turn into a natural disaster. So, I think framing wildfires in the light that they are an ecological inevitability rather than a bad thing is one thing that needs to start shifting.

In addition to that, again, it’s recognizing that they are going to occur. You can—we can continue to spend money on forest treatments and suppressing them, but they’re going to happen no matter what. We’ll never get to the point of domesticating a natural forest like wildfire. So, investing more in that upfront planning of inevitability, I think, is incredibly critical. And then three is shifting our focus away from forest and instead turning it towards home and infrastructure. If we’re talking about wildland urban interface, then we need to start thinking about the urban within that wildland urban interface. And right now, historically, at the federal level and as a society, the inertia within us is to think that we can look at the forest and solve our way out of this. And at some point, given the extreme conditions we’re now facing, we need to think very thoughtfully and deliberately about how, where and under what conditions homes are placed in these increasing risk areas.


RICK WEISS: Great, great points. Thank you. I know a lot of coverage I see seems to be about the wildfire and a mention of how many homes lost, but not really going into the detail of what all that means and why it’s happening that way. Erica, over to you.


ERICA FISCHER: Sure. To build off of what Kimi just said—and she stole some of my points, but I completely agree with this discussion. And so to start off, on the positive note, I have seen a lot of reporters reaching out to scientists and academics to include them in their articles. And I think that is fantastic to get the latest and greatest science out there in mainstream media.

For where I think things can improve—to focus more on that community aspect, that—you know, we are in this situation a lot. A lot of it is because wildfires do have a return period, just like other hazards, just like earthquakes, just like hurricanes. The last time a lot of these wildfires occurred, the communities didn’t exist there. So, these wildfires are predictable. The areas in which they burn—it’s usually the same areas over and over and over again. And so while climate change might be reducing those return periods and the presence of housing might intensify that structure, that climate change isn’t the only reason we’re in this situation. And I see a lot of communities feel disheartened on—and that they don’t have a role to play or they can’t do anything about it or they can’t help themselves if it’s only due to climate change. We are in this situation mainly because of our forest practices and our fire suppression practices over the last hundred years. And it’s really over the last, you know, 20 to 30 years that we haven’t been able to keep up with it. And that’s where climate change has kind of influenced that.

So, I would love to see mainstream media focus more on the bigger story at hand of why we are in this situation and kind of see—you know, focusing on that community planning and empowering communities to move forward and do something about it because they can.


RICK WEISS: Very helpful. And it’s interesting because I and others have lately been banging the drum a little bit to remind reporters to mention climate change when they cover disasters like this—but a really important point, that it’s a lot more than climate change. And the good news there is that we can do more about some of these things than we can do immediately about climate change. Fernando.


FERNANDO ROSARIO-ORTIZ: I would echo what Dr. Barrett and Fischer have stated. I think, you know, there’s been some good coverage and some good emphasis on what the issues are. What I’ve been thinking lately is, you know, there’s—for as much work as we have done in the area, there’s still a lot that is unknown and a lot that needs to be done. And my perception has been that sometimes—you know, obviously we respond to the big issues, but, you know, the long-term implications—you know, contamination or recoveries and all of that kind of get—may get lost. And I think, you know, wildfires are not going to stop anytime soon. I think the race is going to continue. Dr. Barrett mentioned a significant percentage of communities that are now at the wildland-urban interface. And I think, you know, we have to do—as a community, we have to do—continue doing the work of reporting the issues and looking forward to what some of the issues are and bring those to the attention of the stakeholders at local, regional and national level to make sure that we’re prepared for what is going to more than likely continue to be a significant risk.

Are water line contaminants the same around the country?


RICK WEISS: Great. OK. Thank you for those opening question remarks. I’m going to turn now to questions we’re getting from reporters that are coming in. I’m going to start with this from Nick Gerbis at KJZZ Public Radio in Phoenix. A question here for Dr. Fischer—are the kinds of water line contaminants you described the same around the country or only in certain cities or states?


ERICA FISCHER: That’s a great question. We’re—what we’ve seen so far is that one of two things needs to occur for us to see these water line contaminants. The first is depressurization of the water system. And this is to say, to see these contaminants within the water distribution system caused by burning of homes. So, when we see depressurization of the water system, we’re seeing presence of these contaminants. The second is the usage of plastic service pipes. And again, we see this—it’s very common throughout the United States. They’re great materials—very durable, great in a lot of different soils, really highly ductile for seismic resilience. But we are seeing contaminants present when these pipes burn. We’ve tested the pipes at Oregon State University. And there’s other researchers that have tested them at Purdue. The California water board also did some tests on these pipes. We—all three of us, found contaminants in the water due to burning of these pipes. But also, it—we—the depressurization of the water system has occurred in real-life fires—that we’ve seen presence of these contaminants, and we’ve also seen depressurization of the water system.


RICK WEISS: Fernando, anything to add there in terms of the ubiquitousness of these pipes now?


FERNANDO ROSARIO-ORTIZ: I would add to what Dr. Fischer said. I mean, the depressurization of the system is a very important consideration. You know, we had—you know, it’s—for a drinking water system to maintain pressure during a fire, then may require some challenge in—some planning for some big challenges, right?—so the importance of doing that to avoid headaches down the line. I will also point out, you know, when you look at combustion chemistry of pipes and any materials around the home, there’s—there are chemical pathways for the formation of a great number of compounds. And Dr. Fischer and others have done a great job to bring interest and attention to this area. But there’s quite a lot more to learn about not—the compounds that could be precedent and what concentrations are they present and how long. You know, there’s—the cases in California wouldn’t have taken too long to remove them from the distribution system. But that’s—those are the things that we’re looking at, the compounds that we’re looking at. There’s great questions about other compounds that might be present—not that everything is going to be toxic, but it just represents the complexity of the situation that we’re dealing with.

What is impact of fire retardants on the watershed and water quality?


RICK WEISS: OK. We have a question here from Richard Bednarski, who’s with the Sierra Nevada Ally. I’m curious if one of the speakers can talk about the impact of fire retardants on the watershed and water quality. Can any of you address what’s being used to help put out these fires and its potential toxicity.


FERNANDO ROSARIO-ORTIZ: I can address that one. We’ve looked at that—at this question quite a few times. You know, everyone’s aware of the reddish fire retardant that get dropped from planes. That’s Phos-Chek. It’s mostly inorganic salts. There are regulations as to when and how you can apply that fire retardant, including considerations for a potential consideration for water streams, given that it’s mostly inorganic as far as we know and expect, it’s not going to cause significant issues to the drinking water, to the surface waters around that specific application area. Having said that, you know, I know that there might be other things, other compounds, other mixtures that might be added to the—to what—the list of compounds that are used. And obviously, if something different gets cited, you know, it should be looked at. But I do—I’m aware that there’s quite a few regulations that control how these compounds are applied. From the best of our knowledge, we don’t expect significant impacts.

How does the cost of improving to homes to make them fire resistant compare to the cost of responding to the fires?


RICK WEISS: Kimi, were you going to add something there? I wasn’t sure if you were—all right. OK, great. This question, though, might be more for you, Kimi. This is from John Green from the Hutchinson News in Kansas. I wondered if there is an average cost for the hardening or improvement to homes to make them fire resistant? And how does that compare to the cost of fighting the fires and otherwise responding?


KIMIKO BARRETT: Yeah, wonderful question. So, we’ve done some analysis through Headwaters Economics and in partnership with the Insurance Institute for Business & Home Safety, also known as IBHS, who’s kind of one of the leading industries in looking at building construction materials to various natural hazards. And what we found in that analysis, we did it first in 2018 and then again updated, most recently released actually a month ago, particular to the state of California. But that basic mitigation measures in terms of construction materials, also known as home hardening, can be done in a pretty negligible cost differentiation from what would be traditional building materials. So, siding, hardy plank, fiber cement, for example, is much more resistant than wood siding and it’s actually cheaper. Asphalt composition shingles is wildfire resistant, and that’s cheaper than wood shake shingled roofs.

Alternatively, if you go with a metal which is noncombustible, that’s—you’re going to see a cost increase with something like that. But if you take it collectively as a whole, here in the intermountain west, it’s a 2% difference. And, in fact, you actually save money because some of these wildfire-resistant materials are going to be cheaper with longer durability. In California, if you’re going for optimal, meaning the highest wildfire resistance standards for building construction materials like a metal roof, metal decking, structural support system, things like that that are kind of premium products, you’re looking at a price increase of 15- to up to $27,000. So, I think that brings up a really important point, though, that these costs can be done relatively cheaply or affordably because it’s just substituting different products that are about the same level. Having said that, some homeowners may still not be able to retrofit their roof if they have a wood roof and they want asphalt roof. So, there is a need for subsidies to offset these costs for homeowners, and that has to come from state or federal level.

And it should be noted that when you’re looking at I think the second question here of what is being spent right now on things like suppression or forest treatments, it far outweighs what we’re spending for home hardening and built environment mitigation measures. And the best example of that is the upcoming infrastructure act, with which there is zero money for home hardening or belt mitigation measures, including some of the infrastructure that’s needed, which is ironic considering it’s an infrastructure bill. So, the money continues to be spent on forest treatments and suppression, with some money being spent on research and development and some being spent on response and equipment. But there is no money right now in the infrastructure bill being dedicated to homeowner mitigation measures that are very, very much needed. So, these are missed opportunities. And so yeah, I think that would answer your second question.

And then also, I just want to add and plug in that many of these basic mitigation measures that are done to structure and parcel are not actually something you need to hire a contractor out. If things like clearing your rooflines of pine needles or your gutter systems, making sure your deck doesn’t have your propane tank on it during a wildfire, clearing out your vegetation in and around the home, particularly immediately up against the home. So, these are all things that can kind of be done over the weekend that go a long way in reducing your vulnerability during a wildfire.


RICK WEISS: Fantastic.


ERICA FISCHER: I also want to add there to all of the amazing information that Kimi just mentioned, the National Institute of Building Sciences sponsors a report called [Natural Hazard] Mitigation Saves every few years, and they do have these cost benefit numbers that are really digestible for the general public to see how much, like, comparing pre-disaster dollars to post-disaster dollars. And they did include the wildland urban interface hazard in the last two reports. And I can send the link over to Rick to make sure that’s distributed with the material afterwards.


KIMIKO BARRETT: Thank you, Erica. I’m so glad you plugged the NIBS study. Yes. And so to respond and piggyback off that, what they found in that most recent report is that for every dollar spent on up-front wildfire mitigation within the—saves $4 in long-term costs. So, that’s a 1-to-4 ratio. Thanks, Erica.

How do wildfires impact the water supply and water quality?


RICK WEISS: That’s great. Yeah, well, we will get that link. And if reporters want to get that from us, that’s fine. Also, Erica, if you want, you can post that in the chat. But we’ll follow up with reporters as needed. Question next from Shaena Montanari from the Arizona Center for Investigative Reporting. I’m writing a story about how wildfires in northern Arizona could impact the water supply. And it doesn’t seem like a lot of that research has been done here as it has in Colorado and California. What are the best questions I can ask the water suppliers here in Flagstaff, for example, about how wildfire has impacted water quality here or might in the future? Anyone want to give some advice here for how to put those officials against the wall here?


ERICA FISCHER: I’m happy to start us off. We’ve deployed a survey to a lot of WUI communities a few years ago and then just recently to all of the impacted communities in Oregon. So, some of the questions that we asked them is asking them what materials their pipes are actually made out of but also asking them, do they keep records of that? Depending—state to state, it—some jurisdictions keep track of this. Actually, it’s even more nuanced than that. Some water districts keep track of it. Some do not. Usually, the water district is in charge of the pipe up until the water meter. So, it depends on where that water meter is located. In Colorado, in Louisville, it was located on the home itself. In Oregon, it’s located at the curb. So, that changes, you know, the records that the water district may keep in—with—in regards to what pipes are in the ground. So, you can ask them if they keep track of that, what materials they use. And also ask them if they had any depressurization during the wildfire. They will know that. And so you can start—at least ask them those questions to kind of sleuth out if this might have been an issue for them in Arizona.


FERNANDO ROSARIO-ORTIZ: I can add. I mean, I—if the fire is—was mostly in the wildland area and there was limited impact to infrastructure, I would ask, you know, what kind of effects that they’re look—they’re seeing. You know, how do they prepare for it? What are some of the stuff that they’re doing to guarantee continuous operation? You know, questions of the sort, you know, is what we typically end up talking to utilities about. So, good luck.

As building codes can reduce the fire risk to homes, what role does the building industry play in areas with weak codes?


RICK WEISS: Great. Question here from Neela Banerjee at NPR—one of the issues that has come up over and over is the fact that most Western states that are prone to wildfire don’t have building and other codes to reduce the fire risk to homes. Can you talk about why that is? What role does the building industry play in the weak codes?


ERICA FISCHER: So, I’ll—as the structural engineer on the panel, I’ll try to take this. Actually, some of them do have codes. So, the—California adopted the International WUI Code in 2008. And what we actually saw in Paradise was the majority of the homes that were burned down were built before 2008—so, before that regulation came into play. In Oregon, we are actually in the process of doing that right now. In July 2021, Senate Bill 762 was passed in Oregon, and part of that is to address building codes. So, we’re working on that as we speak, as we’re holding this webinar. Washington is trying to do something. So, I think these states are trying. It also, again—and I hate to keep going back to it depends on what state you’re in, but it really does. You know, in California and in Oregon, we—and in Washington, we work their building codes on the state level. So, when there is a new version of a building code that comes out, it is adopted statewide, whereas in a place like Colorado, it’s on the county level. So, the county has to adopt the building code regulation. And county by county is going to vary widely. So, it really depends on how the building code department works in that state. But I think California has traditionally led the way in disaster mitigation. We’ve seen it with earthquakes. And we have, you know, Cascadia subduction zone earthquake risk here in Oregon. So, we’ve always looked to California to kind of see what to do. And they really led the way with this wildfire building code adoption, as well. We are seeing Oregon follow suit. And hopefully, it continues up into Washington, as well.


KIMIKO BARRETT: Yeah, and I would just build off of what Erica just said. There—you know, the building code is just one mitigation tool within that planning toolbox. And it does—it can get adopted at a state level, as Erica just referenced. Here, you know, where I live in Montana, they have adopted a WUI code in theory, but it prevents any counties from adopting anything more stringent than what the state adopted. And the state watered it down so much that it’s just simply symbolic in nature. So, there’s a lot of challenge and nuance to still flesh out with that.

But there are things that can be done locally that I’ve referenced in my presentation, like ordinances and other regulatory devices that can be done at a more discreet basis. But, you know, this isn’t new for us to get pushback from anti-regulatory environment that we live in, particularly in the Western states. But we’ve encountered and overcome things with smoking regulations, with seismic adjustments that we had to do to retrofitting, you know, skyscrapers and other things. So, it’s, you know—it’s our—it’s natural to be skeptical, I think, of building codes and regulations. What we’re coming to, though, is that critical mass and that threshold where we no longer have the choice to say whether this is a good idea or not. We just are seeing too much devastation and will increasingly see so. And so, you know, these are just simply tools that can be done. The city of Austin has adopted the WUI code, as Erica referenced. This is the wildland-urban international code. And they live in a state that is very anti-regulatory in nature. And so, some of these actions are being done at a smaller scale because they’re not going to wait for the state to take action.


ERICA FISCHER: I also want to add—building codes only address new construction, and the vast majority of what’s out there is existing. And I know Kimi mentioned this in her presentation of retrofitting existing structures. This is where the hazard lies. It’s not with our new construction. New construction material, by nature, is probably going to perform better in a fire anyways, even if you don’t do anything special for a wildfire. And so, we have all this existing construction, and then, you know, to tack on something else Kimi mentioned in her presentation, we also have—that our disasters are not affecting everyone equally. So, even if you do pass this new regulation for new buildings, we have all this existing buildings, and we have a very large population that needs help financially as well as with other resources to actually do this work. And so, it kind of goes beyond just, you know, passing the building code. That’s kind of, you know, almost the easy part. But then how do we address all these socially vulnerable communities and help them actually have hazard mitigation that will work?

How long do contaminants from a fire last in a watershed?


RICK WEISS: Great. Question here for Dr. Rosario-Ortiz—how long do contaminants from a fire last in a watershed? Do watersheds essentially cleanse themselves over time, or do some of these accumulate and cause longer-term problems?


FERNANDO ROSARIO-ORTIZ: This is a very good question. We have some information about it. We know—we’ve observed some long-term trends regarding, for example, military mobilization after wildfires. With regards to some of the other species that Dr. Fischer mentioned and I also mentioned, for example, that can be formed in WUI settings or could be also potentially observing wildland settings, I don’t think there’s enough information out there. We do have anecdotal evidence from some utilities where they see kind of return to baseline conditions within a few years. But a lot of the times, you know, there’s a lack of long-term monitoring that will answer questions like that.

Can these contaminants be easily removed with commercial filtration systems?


RICK WEISS: There’s a related question here about whether a regular Brita or other commercially available water filter would be enough to make water drinkable after it’s been contaminated by leaching from melted pipes or ash that’s been sucked into the system. I know you may not want to endorse particular brands, but can you say something about whether these are easily removed with commercial filtration systems?


ERICA FISCHER: They’re not.


RICK WEISS: They’re not.


ERICA FISCHER: And on top of it, we often suggest that jurisdictions issue do-not-drink notices rather than do not—rather than boil water notices. So, it’s a do not drink, do not boil water notice because boiling the water actually will release it into the air, and people can still inhale the compounds.


FERNANDO ROSARIO-ORTIZ: I’d like to add that, you know—follow the guidance from your local utilities. Do believe that when these situations happen, the personnel in your local water utilities are working very hard to guarantee the safety of your water. So, please listen to the communications that comes from them. They’re trying to improve the situation.

What is known about how many structures lost to wildfires are rebuilt in the same exact location?


RICK WEISS: OK. And I think we have time for one or two more questions here. For Dr. Barrett, you shared some stats about the number of buildings and homes lost to wildfires. What is known about how many of these structures are rebuilt in the same exact location?


KIMIKO BARRETT: Yes, there is a great study that was done, and I think it’s already ten years old at this point. Volker Radeloff out of the University of Wisconsin looked at this very, very closely. And what they found is—it’s a bit discouraging, actually—is that—I want to say the statistic is 65 to 70% of homes are rebuilt in the exact same wildfire perimeter, almost to the exact same conditions. And so I would reference that study. I can dig it up here. It’s a PNAS article, but it’s a great read. And it does indicate, you know, these trends are all increasing, and then it’s very natural to rebuild in an existing wildfire perimeter that’s historically burned or most recently burned and that, in fact, usually the planning process is expedited and all anticipatory or preventative measures to, you know, limit another similar disaster are waived in order to expedite that process of rebuilding.

How big of an issue are disinfection byproducts after a wildfire?


RICK WEISS: And let me do one last question before we do a wrap-up here. From—follow-up from Shaena Montanari from Arizona Center for Investigative Reporting—how big of an issue are disinfection byproducts after a wildfire? Not sure what those refer to.


FERNANDO ROSARIO-ORTIZ: I can take that. So, disinfection byproducts refer to the compounds that are formed upon the disinfection of water—reaction between hypochlorous acid and the organic carbon that is present in the water. Disinfection byproducts are regulated by the EPA. Utilities are going to be required to sample quarterly for those. Going to the specific question, what we observe is there are changes to their formation when you have a wildfire. The reality is the effects are quite complex. In some cases, we observe what is—will be expected will translate into a decrease in formation. In other cases, for—under certain conditions, we have observed an increase in formation. The reality is, in terms of, like, public health, unless there is a significant fire where a big percentage of the watershed has been combusted and the utility only have—has that water source, I think for the most part, we don’t expect them to be a significant concern. You know, also—point out to the fact that a lot of the times, these utilities are going to have more than water—one water source. So, the fact that a watershed was impacted, you know—if you’re—utility, for example, in a big city, they will have other sources. So, they have the capacity to switch to other sources and wait it out to—for example, wait until the worst conditions go by before switching back to the other source.


RICK WEISS: Sounds like that’s actually another question we could add to the list we were talking about earlier to ask utilities is, what kind of capacity do they have to take water from another source from a while—for a while if they need to?



What is one key take-home message for reporters covering wildfire resilience?


RICK WEISS: So, we’re going to wrap up over the next few minutes. I want to ask each of our guests today to give reporters here a take-home point, something they really want to emphasize, often very strong points to leave people with. Before I do that, I just want to remind our attending reporters that as you sign off today, you’re going to see a prompt for a very short, three-question survey. Everyone hates surveys, but we love this survey because it really helps us find out what you need, what you like, what you want next in media briefings. So, please take that half a minute or a minute it takes to fill out that survey and tell us how we can keep these things as useful to you as possible. Now I’d like to just go around and ask each of our experts today just to offer up a take-home point, if there’s one thing you really want reporters to walk away with and keep front of mind. And I’ll start with you, Kimi.


KIMIKO BARRETT: Yes. So, I always like to leave with this idea of hope that we can solve this. We’ve solved it before in the past. If you look historically at western settlement across the country, we built our—entire cities made with nothing but combustible, burnable materials. And they kept burning down over and over and over, like the 1906 San Francisco fire, the Peshtigo fire, with which—1,700 people died in one wildfire. That’s astronomical. And we stopped at one point and said, hey, we’re going to start doing things differently. So, we put in fire hydrants. We replaced our sawdust for insulation with noncombustible materials. Well, I think maybe the doctors—the other panelists would argue with that. But what I’m saying is that we replaced our sidewalk, which was boardwalk, with concrete, and we did these things to start thinking very thoughtfully and deliberately about what and how our urban areas were designed with fire in mind. So, we’ve solved this before from an urban planning perspective. We can apply those same principles, those same lessons now to the wildland-urban interface.


RICK WEISS: Great. Thank you. Erica.


ERICA FISCHER: To stay on the positive note as well, I—you know, we do understand how to do this. A lot of the research that has come out of this area on how to build houses that are resilient to wildfires in the WUI—a lot of that research occurred in the late ’90s, early 2000s. So, we have had this knowledge for a really long time. We also already know how to tackle community resilience. We’ve done it for earthquakes, for floods, for tsunamis. We’ve done it in a really successful way for our communities. And so I think it’s about finding ways to partner this together, to learn from how we’ve done it before and move forward on this. I’m very hopeful by the involvement of more engineers in this space, community planners and zoning officials who are trying to carve out a space for themselves in the WUI discussion and solve this problem.


RICK WEISS: Thank you. And Fernando.


FERNANDO ROSARIO-ORTIZ: I will—I would echo the positive message. You know, we’ll—we’ve handled other challenges before in our history. We can do this. But also, looking into the future, this is a complex issue that involves not only engineers and planners, you know, foresters and many different organizations at the state and federal level. I do think that we—it’s good for us to work together and identify some of the more important questions that we need to do, bring multidisciplinary teams together so that we can have a better understanding of, you know, whether combustion of pipes is a main source or whether the combustion of everything in the house is going to give you the same thing, and we have to look for materials that are different, that might be more—would be most cost-effective and that will allow us to lower the risk. I remain positive, but we have some work ahead of us. But luckily, we have the talent. We just have to bring it all together in one room and provide solutions.


RICK WEISS: Fantastic. Well, I want to thank all three of our experts today who have helped bring that story of all that’s needed to address this complicated problem to reporters who can now move ahead, I hope, with more facility to cover this topic. This has been a fantastically educational media briefing, and I thank you all. And thanks to you reporters for attending. Please do hit the survey at the end. Please follow us on Twitter @RealSciLine, and check out our website, And to all of you, thanks again. We’ll see you at our next SciLine media briefing. So long.

Dr. Kimiko Barrett

Headwaters Economics

Dr. Kimiko Barrett is the lead wildfire research and policy analyst at Headwaters Economics, a nonpartisan independent research organization based in Bozeman, Montana. She is also the program director for Community Planning Assistance for Wildfire, working with more than 80 communities across the country to devise community-driven solutions to reduce wildfire risk and increase community resiliency. Dr. Barrett was recently selected as member of the federal Wildland Fire Mitigation and Management Commission, providing key federal policy recommendations to better address wildfire impacts and risk reduction strategies. In partnering with institutions, community leaders, local government, and other subject matter experts, she has led research of national significance on topical issues such as the true cost of wildfires, constructing wildfire-resistant homes, building codes and land use planning, and measuring wildfire impacts through structure loss.

Declared interests:


Dr. Erica Fischer

Oregon State University

Dr. Erica Fischer is an assistant professor of civil and construction engineering at Oregon State University. Dr. Fischer’s research interests revolve around innovative approaches to improve the resilience and robustness of structural systems affected by natural and man-made hazards. She has participated in post-earthquake reconnaissance team missions in diverse regions including Haiti, Napa, California, Italy, and Mexico City; and led post-wildfire reconnaissance after the 2018 Camp Fire and 2021 Marshall Fire. Dr. Fischer has experience as a practicing structural engineer and holds a Professional Engineering license in the states of Washington, California, and Oregon. She is a member of the Board of Directors of the Earthquake Engineering Research Institute and co-chair of the ASCE Fire Protection Committee.

Declared interests:


Dr. Fernando Rosario-Ortiz

University of Colorado Boulder

Dr. Fernando L. Rosario-Ortiz is a professor of environmental engineering at the University of Colorado Boulder. He also serves as the associate dean for faculty at the College of Engineering and Applied Science and as associate editor for the journal Environmental Science and Technology. Dr. Rosario’s current research focuses on environmental photochemistry and the impact of wildfires on water quality.

Declared interests:


Dr. Kimiko Barrett presentation

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Dr. Erica Fischer presentation

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Dr. Fernando Rosario-Ortiz presentation

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Natural Hazard Mitigation Saves: 2019 Report