Community destruction during extreme wildfires is a home ignition problem

burned homes
US Forest Service photo

By Jack Cohen and Dave Strohmaier

We must abandon our expectation that we can suppress 100% of wildfires and reject the false narrative that community protection requires wildfire control. Community wildfire disasters have only occurred during extreme conditions when high wind speed, low relative humidity, and flammable vegetation result in high fire intensities, rapid fire growth rates, and showers of burning embers (firebrands) starting new fires. Fire agencies primarily use wildfire suppression tactics for protecting communities from wildfires. But as we see from current extreme wildfire conditions in California, Oregon, and Washington, fire suppression can quickly become overwhelmed and ineffective.

Wildfires, and thus extreme wildfires, are inevitable. Does that mean wildland-urban (WU) fire disasters are inevitable as well? Absolutely not! WU fire research has shown that homeowners can create ignition resistant homes to prevent community wildfire disasters. How can that be possible?

aerial photo Paradise Camp Fire
Paradise, California, off Herb Lane near Skyway in Paradise. From Butte County drone mapping project. November, 2018.

Recall the destruction in Paradise, CA, during the extreme 2018 Camp Fire. Most of the totally destroyed homes in Paradise were surrounded by unconsumed tree canopies. Although many journalists and public officials believe this outcome was unusual, the pattern of unconsumed vegetation adjacent to and surrounding total home destruction is typical of WU fire disasters. In 2020 we see the same patterns of home destruction and adjacent unconsumed vegetation in photos from Malden, WA, and Phoenix, Talent, Blue River, and Mill City OR. Home destruction with adjacent unconsumed shrub and tree vegetation indicates the following:

burned home
U.S. Forest Service photo.
  • High intensity wildfire does not continuously spread through a residential area as a tsunami or flood of flame.
  • Unconsumed shrub and tree canopies adjacent to homes do not produce high intensity flames that ignite the homes; ignitions can only be from burning embers and low intensity surface fires.
  • The “big flames” of high intensity wildfires are not causing total home destruction.
structures burned Almeda Fire Phoenix Talent Oregon
The Almeda Drive Fire in the area of Phoenix and Talent in southern Oregon. Image by Jackson County, September 8, 2020.

Surprisingly, research has shown that home ignitions during extreme wildfires result from conditions local to a home. A home’s ignition vulnerabilities in relation to nearby burning materials within 100 feet principally determine home ignitions. This area of a home and its immediate surroundings is called the home ignition zone (HIZ). Typically, lofted burning embers initiate ignitions within the HIZ – to homes directly and nearby flammables leading to homes. Although an intense wildfire can loft firebrands more than one-half mile to start fires, the minuscule local conditions where the burning embers land and accumulate determine ignitions. Importantly, most home destruction during extreme wildfires occurs hours after the wildfire has ceased intense burning near the community; the residential fuels – homes, other structures, and vegetation – continue fire spread within the community.

Uncontrollable extreme wildfires are inevitable; however, by reducing home ignition potential within the HIZ we can create ignition resistant homes and communities. Thus, community wildfire risk should be defined as a home ignition problem, not a wildfire control problem. Unfortunately, protecting communities from wildfire by reducing home ignition potential runs counter to established orthodoxy.

There are good reasons to do “fuel treatments” for ecological and commercial objectives. But the greatest fuel treatment effect on wildfire behavior is within the fuel treatment area; fuel treatments do not stop extreme wildfires. So let’s call a spade a spade and not pretend that many, or even most fuel treatment projects actually reduce home ignition potential during extreme wildfires. Because local conditions determine home ignitions, the most effective “fuel treatment” addressing community wildfire risk reduces home ignition potential within HIZs and the community. Wildfires, exacerbated by climate change, will occur. Community destruction during extreme wildfires will continue as long as wildfire suppression remains the primary approach for community protection. Conducting the same ineffective strategy and tactics expecting different results will continue to be a recipe for disaster when it comes to protecting homes from extreme wildfire.

To make this shift, land managers, elected officials, and members of the public must question some of our most deeply ingrained assumptions regarding fire. For the sake of fiscal responsibility, scientific integrity, and effective outcomes, it’s high time we abandon the tired and disingenuous policies of our century-old all-out war on wildfire and fuel treatments conducted under the guise of protecting communities. Instead, let’s focus on mitigating WU fire risk where ignitions are determined – within the home ignition zone.

For further information:

Jack Cohen, PhD, retired US Forest Service Research fire scientist determined how structures ignite during extreme wildfires, created the home ignition zone concept, and co-developed NFPA Firewise USA.

Dave Strohmaier is Missoula County Commissioner. He previously worked for both the Bureau of Land Management and US Forest Service in fire management, and has published two books on the subject of wildfire in the West.

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54 thoughts on “Community destruction during extreme wildfires is a home ignition problem”

      1. They most certainly did say that.

        Contrary to their assertion that they are battling outdated theories, these authors are desperately searching for a way to resurrect proven-false theories that support the rejected policies that have resulted in wildfires achieving heat levels and ultimate environmental impact far greater over the past few decades than those that naturally occurred prior to wildfire “management”, and to shift the blame to the homeowner victims.

        “In 2020 we see the same patterns of home destruction and adjacent unconsumed vegetation…” Yes, and if you bother to look yards or miles away from burned structures, you ALSO see the pattern of burned timbers and underbrush immediately adjacent to unconsumed vegetation. This is the nature of fire, not a special discovery about how structures ignite.

        These authors are guilty of the worst kind of pseudoscience. Just because someone uses scientific terms like “experiment” and “studies” doesn’t mean they adhere to scientific rigor.

        Cohen and Strohmaier may be extremely earnest — but they are also extremely wrong.

        1. Interesting. Can you supply any evidence or studies in support of that position. Please quote the part of their text where they said that if a home burned in a wildfire, it was the resident’s fault.

          Can you explain how the flame front of the wildland fire ignites property in unburned areas?

          Have you written anything that expresses your analysis?

        2. Just curious what your credentials are Daniel. I noticed your criticism of the authors of being guilty of “the worst kind of pseudoscience”. Have you researched the effects of wildfire on home ignitions as well?

        3. I don’t know you, but I do know Jack Cohen, and after working with him, I trust what he says when he states, “The house that doesn’t ignite, doesn’t burn”.

        4. The outcomes of many tens of thousands of burned structures over a century of firefighting experience in a dozen western states support their conclusions. Your position is untenable.

        5. I and my neighbor just lived through the glass fire, and defended our homes while wild fire was raging 360 Degrees around us.

          The situation described by the author’s is exactly what we experienced. There were massive flames just a couple hundred feet away. Fir trees crowning with flames at least a hundred feet high above them.

          It was after the most intense fire was gone that we had a few slow starts from Embers on a deck and a fence. We were able to put them out.

          1. In the Cedar Fire, a retired firefighter and his wife started to evacuate. Halfway down their long entrance-way he saw the fire top a ridge about four miles away and turned around. They filled the bathtub and sinks with water, and when the flame front was passing embers were being blown through the weatherstripping on the door, immediately starting “spot” fires on papers, upholstery, and anything else that resembled tinder. They kept going through the house dousing the fires while they were small and the flame front was passing (a few minutes, as it was being pushed by a 40 mph wind). After passage, they went outside and hosed down everything burning and then mopped up hot spots. They saved their lives and their house. Most, if not all, the deaths were those evacuating. A friend was stalled on an evacuation route (the only one) for a long time, but the traffic got moving just in time and they survived.

            That made me think more about sheltering AND DEFENDING in place. I couldn’t help but wonder if a crew that got caught in their vehicles at a house they were sent to defend at the top of a steep ridge might have survived if they had sheltered in the house instead. No Monday morning quarterbacking, and I don’t blame their boss–blame is NOT the point. Several friends of mind lost their homes, one had plenty of defensive space, but the grass cut to two inches ignited the wooden porch on his steel home, and the place was gutted. Another friend had built a house to the strictest standards but lost it. He said that the bathroom window had “blown” OUTSIDE.

            So it’s not about fault, it’s about CONTEXT, the circumstances one is faced with and a judgment call that had to be made. Because someone happened to not know what all their options were does not make them at fault. In some circumstances, evacuation may be the only option. Context again.

            It seems to me that all these anecdotes need to be assembled into data so we don’t have to keep doing the same things all over again and expecting different outcomes.

  1. Homeowners need to take more responsibility for mitigating chances of home ignition. There are pro-active things that can be done to hep prevent their houses from burning. Defensible space surrounding the home is important. Fire suppression devices (sprinklers, water supply, etc) are important. Home materials are important (metal roofing in high risk areas) are important. Lots of things homeowners can do to help prevent their homes from burning.

  2. Would like to see better data on what is happening in these subdivisions where homes are much closer together than the 100′ mentioned as some sort of benchmark?
    It just seems natural that a high radiant heat component is at play and contributes to the house to house propogation….like I said…want to see much better, detailed data.
    I do agree with their point about ignitions from embers…..many structures burn after the fire front has passed due to numerous ignitions that rain down.
    For those of you who have never experienced it, try to imagine a hurricane of blowing embers/chunks of debris on fire getting blown into every imaginable crevice on/around your home.

    Towards this point, there is much a home owner can do due to fireproof a home/adjacent property.
    Unfortunately, I don’t see much of an effort from the “suppresion” agencies, whether they be state or federal to invest and work in this direction….
    “Firewise” programs don’t seem to be getting the traction and resources that would make a difference, imo…
    I live in a high risk wildland/semi-rural environment and breathe a sigh of relief evey year once we are past our peak fire risk, which is typically (fortunately) only about 6 weeks.

    1. This is an excellent article
      as a wildland fireman since 1974 this is what I’ve seen is why houses burn It’s easy to do way ahead of time it’s hard to do when the fires in the backyard defensible space and defendable home.

    2. Here’s some heavy reading:
      if you don’t want to wade thru the whole report, here’s a slide show:

      Here’s a USFS study on CA fire losses that shows interface developments have the highest losses: Which begs the question; if they have the highest losses, why do we build them?

      The “suppression agencies” are not responsible for permitting developments that are spaced 4 to 6 to an acre and located in wildfire hazard areas. The suppression agencies suppress fires.

      Agencies that are responsible for building codes, accepting various fire codes, mitigation standards, zoning, and development proposal approval are the ones who are building problems faster than the “suppression agencies” can protect them. The local government authorities permit the structures that are far too close to each other and cannot comply with the recommended 100′ mitigation standards because a property owner would have to bulldoze their neighbors house in order to comply with 100′ mitigation. Counties and other development permitting agencies have no idea how to safely develop in the WUI. Many of them, unless pressured by citizens, utilize the same standards that would be used in a suburban environment with a fire hydrant on every block, stricter building / fire codes, protected by a large well equipped municipal full time fire department, and and as a result, what we get in our semi-rural environment is a suburban development “transplanted” into the WUI, ready to burn. No hydrants, protected by a small volunteer fire department, a large nearby wildfire threat, less than adequate building/ fire codes, and 100′ mitigation standards that we cannot comply with.

    3. The subdivisions that burned in the Waldo Canyon Fire in Colorado a few years ago are a good case study in the effect of radiant heat from structure fires igniting adjacent homes less than 100′ away.

      1. As I recall, studies in the 1960’s found that the radiant heat limit for structure ignition for wildland fires was a little less than 30 feet.

        Since a structure fire burns hotter and longer, I presume that the distance would be greater from structure to structure, so why do we build houses a lot less than 20 feet from each other? I can only conclude that adequate suppression forces and very short response times are included in the excuses.

  3. Are you suggesting that homes themselves need to be more fire resistant or the immediate area surrounding a home?

    1. Both are necessary to make your home robustly firesafe. Neither one is really sufficient without the other.

  4. One thing I feel very strongly about, this whole narrative of “climate change” being the root cause of these fires is, in my own personal, honest and humble opinion, a cop-out and an excuse.

    I cannot prove nor disprove that “climate change” is or is not exacerbating the problem. But “climate change” does not start a fire on a red flag day.

    I think more needs to be done to keep people out of dangerous areas on red flag days. For those who must go there, better education is probably needed. And, utilities need to fix their power lines. The Wall Street Journal reported that several blazes (but not all) in Oregon were started by high winds blowing trees into the wires. Climate change didn’t do that either.

    And yes, brush needs to be cleaned up and trees thinned and prescribed burns performed. In one sad case, the people of Berry Creek, Calif (also reported in the WSJ) wanted to thin trees and clear brush in their community. Red tape at the state level held the work up for TWO YEARS! They, finally, finally, FINALLY got the green light to go ahead when the fire broke out and destroyed their community.

    Is government bureaucracy part of the problem here? Again, “climate change” did not hold up that work for two years !

    Fred M. Cain

    1. Here is an excerpt from an excellent article at, titled “As wildfires rage, climate experts warn: The future we were worried about is here”:

      But no matter where they occur, wildfires need two main ingredients to sustain themselves: conducive fire weather — dry conditions together with lightning and wind, for instance — and “fuel,” which in this case refers to dead trees, dried-out leaves and any other material that can burn up.

      Seasonal wildfires occur naturally around the world, but as temperatures rise due to global warming, the atmosphere can more efficiently pull moisture out of leaves, pine needles and the forest floor, said Mike Flannigan, director of the Western Partnership for Wildland Fire Science at the University of Alberta in Canada. Without precipitation to compensate, this can create ideal conditions for a wildfire.

      “It makes it easier for fires to start, whether from a lightning bolt or somebody’s campfire,” Flannigan said. “It also becomes easier for fires to spread because there’s more fuel to burn, which means we can get these higher intensity fires that are difficult or nearly impossible to put out.”

    2. I suspect Wallace, ID was not burned by a 1910 firefront, but by the ember shower on very susceptible buildings/homes that the authors are alluding to. Climate change certainly could make these UI catastrophes occur more often, but it has been already happening for many – many decades; well before the climate change concept was even coined. Whether you believe climate change is occurring or not, ember showers/storms have occurred and has burned available fuel for many decades. Their point of healthy forests treatments and fuel treatments are all well and good to do, or a feel good, but it ultimately comes down to ember traps and how close together the buildings are. My feeling is that building codes and insurance rates have to reflect the danger of building anything in a fire environment.

  5. This piece should be syndicated and made more widely available, and distributed to schools, setting the world’s mind on fire with a fresh (however, Jack has been doing excellent work on this, both at the research level and with popular communication efforts for years) approach. I haven’t met Jack personally but once talked with him on the phone while the Cedar Fire was burning in 2003.

    Sometimes reality comes as quite a shock to people, and can easily be misinterpreted.

    For years I have noticed that a lot of the fire suppression folks have ignored and even been hostile to Jack’s and other USFS Fire Lab scientists’ work, clinging tenaciously to tradition. I hope work like Jack’s is making some inroads into that bias.

    When I tried to get in touch with Jack just after he retired, the person with whom I spoke sniggered, leaving me with the impression that he had been replaced by someone who didn’t appreciate his work. I didn’t get the contact info, and haven’t been in communication with him for years. I sure hope that someone at Missoula still appreciates him. I hope I got the wrong impression . . .

    1. Hi Wayne – I really appreciate your comments and your perspective! I’ve worked for NFPA for almost 20 years and have been privileged to learn so much from Jack Cohen and other fire scientists and researchers about how homes ignite and the array of strategies we need to begin to eliminate the mass destruction of homes we see during large wildfires. My job is to help translate the research and science into practical information for residents and the fire service. We’ve used Jack’s research and worked with others including NIST and IBHS (Insurance Institute for Business & Home Safety) for many years to better understand how homes ignite and what we can do – as fire managers, policymakers, local officials, homeowners — to create ignition-resistant communities. As Jack’s short bio above indicates, he was a co-creator of the Firewise USA recognition program which NFPA has administered since 2002. NFPA just produced a short video piece that includes a clip of one of the early educational videos that NFPA produced with Jack (see it here: He has been a stalwart messenger for the need for ignition-resistant design, siting, construction and maintenance of homes for many decades now. I have no idea about who appreciates him in Missoula, but I will say that more than 1,700 communities participating as Firewise USA sites in 42 states have been inspired by and embrace his work.

      1. Michelle, thanks for your good work. The video makes a lot of the points I keep trying (apparently not hard enough) to make.

        Two points:

        1. I spoke with Jack Cohen on the phone while the Cedar Fire was burning in 1970. I have forgotten most of what he said, but in that infamous cul-de-sac (hated my me and the Fire Marshal when I was on the local Subdivision Advisory Committee in the 1970’s, be we were always outvoted) that burned in the Scripps Ranch Subdivision and was all over the news, he noted that the big eucalyptus trees were scorched on the house-side, not the flame-front side. I would say that not even one house should be allowed to burn, or as we saw, every house would burn. We need a heat-sensing camera on a blimp to see the sequence. That means, in my mind, that every single house should have self-contained, automatic, remote controlled interior and exterior fire suppression systems. Furthermore, I believe that our tax money would be better spent than the made for TV dramas that we see on the TV news. I want to scream when I see gross ineptitude playing out before my eyes, totally unnoticed by the buyers of breakfast cereals and beauty products looking at the same thing and buying it.

        2. More aviation assets, both tactical and strategic, flying sorties during alerts, and more closely supported support facilities.

        As my grandpa used to say, “I feel a fit comin’ on!”

      2. I believe appreciation for Jack and his work is growing, and surely many at Missoula Fire lab must see it’s value. Jack was awarded the first National Legacy Award by the USFS when he retired. I also believe he paid the price while working with the USFS for following the science, and not allowing an institutional perspective to affect his science or conclusions.

        There are many WUI residents whose homes may be saved by following his directions on fireproofing both the land around homes and homes themselves. Likely lives saved. He is appreciated.

        Homeowners have to take responsibility for their own home burning if they have not done the right things to protect their property. They choose to live in the WUI. In my WUI community many people recognize our own responsibility and do not ask the Forest Service to do fuel treatments in the forest to protect our homes.

        I do disagree with Jack and Dave Strohmaier that there is good reason to do fuel treatment projects to promote forest health. There may be light-handed versions of thinning and burning that could do so, but the widespread and intensive treatments generally done by Federal and State agencies tend to have the opposite effect and cause forests to become barren and ecologically dysfunctional.

        Jack could be kicking back and enjoying his retirement and I think he would like to, but he seems driven to give the knowledge he gained from decades of research to those who can benefit.

  6. I took the point of the article to be that the home ignition zone was the most important factor in survivability of a structure during a wildfire, and therefore should be a top focus for communities in risky environments. I’m curious how that point is wrong.

    That could, of course, be heard as ascribing fault to a homeowner, and every individual case is going to be different and very hard to pin down to one exact cause. However, as a homeowner in the WU I have a choice to harden my property against fire, or not. If I ignore the environment where I live and the challenges of building construction and don’t address critical vulnerabilities, don’t I share at least some responsibility for a bad outcome if a fire impacts my neighborhood?

    1. Yes, homeowners certainly share some substantial responsibility for the fire safety of their property. The geography of communities, ignition patterns, and fire spread matters very much for community wildfire safety. But the bottom line is that the best way to make sure your house doesn’t burn down is to make your house really fireproof. And that’s up to the homeowner pretty much.

      I’ve spent years trying to think of good talking points to help illustrate this lesson. Here’s one, maybe a bit silly:
      If a homeowner fails to install a waterproof roof on their house and/or fails to properly maintain it in the long run then their roof will leak when it rains and their house will get wet inside. In that case it would not be reasonable to expect some agency of the federal state or local government to show up at the first hint of rain and hold an umbrella over their house and assume complete responsibility for keeping their house dry. It’s up to homeowners to build and maintain a waterproof houses.

      It doesn’t rain all the time, and even the house with the leaky roof will stay dry during a dry spell. But homeowners need to be prepared for rain before the rain comes. Once the rain starts falling it’s too late to do anything more than very quick and temporary emergency work – like maybe throw a disposable single use tarp over the roof and hope it doesn’t blow away. Any politician trying to make political hay out of the fact that the other party failed to hire enough government umbrella holders to come and save your leaky house from the rain is just blowing smoke.

      What do you think? Too silly? On target?

      1. With respect, Taylor, the comparison doesn’t hold water.

        Fire is a community problem, therefore there needs to be a community solution. Not every structure is the same, and not all owners are the same. For example, on one extreme there are people, no doubt like yourself, who are young enough and rich enough to repair and install all of the fire-safe improvements needed, but imagine an elderly widow living alone on Social Security in a hundred year-old shack. She should be able to depend upon her neighbors, her community, and yes, the government, to help make her house fire-safe instead of a fire-trap that could kill her and be a hazard to neighboring structures. In addition to making her homeless or being burned alive, her house could set adjacent homes on fire or be a source of airborne burning material that puts distant homes at risk.

        1. Fire is a public policy problem. If the government got behind it, they could provide free safety inspections and installations for people who can’t afford it. They could force developers to install sprinklers, etc. And they could deny people the right to develop high danger areas. The fact is, this isn’t Canada, and we don’t have that kind of government. Sorry to get political, but this is a political issue.

  7. Thank you for this article! I’ve learned by talking to both my local fire agencies, a semi-retired fire scientist, and taking acollege course on fire ignition and behavior, that structures are a massive vulnerable piece of complicated fuel. They must be hardened first and foremost. Most structures burn from the top down statistcally (according to a video put out last year by all 9 California Bay Area counties). As a licensed landscape architect and fire/landscape lecturer, I can explain how climate is changing our flammability easily, how the firewise program is well meaning but stops short of what we really need, and how this stuff all is fitting together. It’s no more of a cop-out than covid is a hoax. I hear all too often that hardening a home is expensive,so that’s why someone won’t do it. THAT is a cop-out. Homeowners aren’t being blamed for owning vulnerable structures, but I do feel that they can’t reasonably cry foul when they fail to evolve their approach with new understanding of how structures burn, why they ignite, and how wildfires behave. Kudos to the authors! A spade IS a spade.

  8. The Cerro Grande fire that burned about 1/3 of Los Alamos was my first real experience with a wildland/urban interface fire. It was obvious that the fire wasn’t carried by the timber interspersed with the houses. It was carried house to house. Large amounts of the interspersed vegetation was singed or unburned. Trees were scorched on the side facing houses and green on the sides away from the burning structure. I didn’t see this on some properties – this was the burn pattern time and time again. Since that experience, I’ve seen this type of burn pattern occur over and over again.

    This isn’t to say that vegetation management is a waste of time and money. It certainly isn’t, but the lack of real emphasis on structure hardening is a glaring failure on our parts to prepare our communities for the possible severe fire event.

  9. I sponsored a seminar back in the last century, at which a fire researcher from the Western Region Fire Lab gave a paper that included the following (paraphrased): “Even in the hottest wildland fires, the flame-front does not consume fuels larger than one-half inch in diameter.” This does not mean that thicker fuels will not burn, only that they don’t burn in the flame-front. Have a post-burn look at the smallest remaining twigs on the shrubs (the shrubs look like blackened staghorn-like skeletons) after a big, super-hot fire. Counter-intuitive isn’t it?

    I once had a house on the edge of a canyon in Southern California. Using nothing bigger than a one-handed pruning saw or a lopping shear/hand pruner, I limbed up the big shrubs, and cut back the small ones. I removed all of the cuttings; they went to the composting facility. No chain saw needed.

    One of the worst ways to create defensible space is to CLEAR off the vegetation. Remember, defensible space does not necessarily mean that it will be defended. Particularly in fast-moving, firebrand/ember fires, it’s unlikely that crews will be asked to risk their lives at the leading edge. What one really needs is a fuel-separation strategy to separate fuels enough (it only takes a few feet) horizontally and vertically and prevent flash fuels like annual grasses and some other weeds from growing. The shade from the shrub canopies will minimize weed growth, and the soil should be left undisturbed. Ma Nature is a persistent old cuss, and she will give you a highly flammable weed patch that can be ignited with the slightest spark or old piece of glass–it’s just waiting to ignite and spread rapidly. Ever see a fire break burn? Even the shrubs that grow back will start out with branches smaller than a half-inch. Even worse is chipping a bunch of future firebrand fuel and leaving it on the ground. Doing it this way minimizes the NEED for defense; it should burn itself out. There’s more, but you get my drift . . .

  10. In Canada, the use of sprinkler deployment and home owner education has become a top priority. During the massive wildfire at Fort McMurray in Northern Alberta, where over 2,000 homes were lost, the average home was over a mile from the actual fire line. And, interestingly enough, there were very few sprinklers deployed during this event. Burning, wind blown embers were responsible for the vast majority of homes lost.

    British Columbia Wildfire Services has embraced the use of sprinklers and home owner education in order to continue to reduce risk. Homeowners can no longer count on state or provincial authorities to protect their property as the amount of fires along with the ferocity of fires makes this impossible. Homeowners must begin to take more responsibility for the protection of their property. It’s not blame…it’s reality. And it will get worse. Much worse when you can’t get insurance for fire on your home at any price. No insurance…no mortgage…no value (or greatly reduced property value).

    The US should open its mind when it comes to wildfire and look at other countries, such as Canada, Australia and European nations to get better ideas on how to direct wildfires and steer them around assets, rather than trying to put the fires out. There are no perfect solutions, but if you keep doing what you always do, and expect different results, well…best prepare for more Paradise events or worse, when even larger communities burn.

    That’s reality. Not arguing climate change. Not finger pointing. Reality is staring everyone in the face. Just have to open your eyes to see it. You can’t just throw manpower at the problem. It’s not working and lives are being lost because of it.

    1. VERY well said, and it’s high time. I first got the idea from an Australian in 1970 during and after the Kitchen Creek Fire, when I was researching the literature. He lived in the outback, and built his own system. I have been trying to advance his idea ever since, to deaf ears. He built a 6000 gallon (Imperial?) tank, and “sprinkled” his house with a wind-resistant design of his own, with an auto-start 350 gpm high-pressure pump, started by signals from thermocouples set in the bush. Today, we might use a remote-control or staying in the house, putting out any little fires by hand. A retired firefighter did just that in the Cedar Fire where most, if not all the deaths were those evacuating. He said the pressure differential on flame-front passage “pushed” firebrands right through the weather-stripping on his doors, and he and his wife kept dipping water out of the bathtub and sink to douse papers, furniture, etc. After flame-front passage, he went outside and mopped up.

    2. Hi Randy – thanks for your comments and point of view. I am NFPA’s Wildfire Division Director – we administer the Firewise USA program across 42 states and collaborate with our Canadian colleagues on their promotion of FireSmart and other public outreach activities. All of what we strive to teach residents and local decision-makers is based on the decades of research by Jack Cohen and a number of others about the home ignition zone and the need to create ignition-resistant communities. My team gets a lot of questions about exterior sprinklers, and while I’m aware of some research and data, it seems as though this particular strategy is still questionable in terms of effectiveness. Do you know of a good data source that would speak to performance of the approach as used in BC or other parts of Canada? Thanks for any insight you can provide.

      1. I have heard this too, I’ve been told two things but I would love a credible source. I understand that part of the problem is that a home system in an intense event would wind up merely misting and not being effective. I’ve also heard conjecture that if enough homes did this, it could impact water pressure needed at the hydrant. One farther fetched concern I would have is the diy or uninformrd type of installation where irrigation components might be relied on, not the more heat tolerant fire sprinklers. Looking forward to other replies to Ms. Steinberg’s question.

      2. Hi Michele. My company, Wasp Manufacturing Ltd., has specialized in sprinkler protection products for almost a decade. I don’t want to turn this into an advertisement but the background is important. We provide what is known as a Type 2 Structure Protection Units (SPUs) which are based on the specifications which are provided by British Columbia Wildfire Services, the provincial authority for structure protection in the province. These specifications have been created over 20 years and each Type 2 has 6 gas powered Mark 3 pumps, portable water bladders and enough sprinklers to protect up to 100 or more houses when deployed off a hydrant line. Wasp has a fleet of 10 of these SPUs which we provide as rental units when needed by the province during wildfire events. These Type 2 units are also recognized by most if not all Canadian provinces along with the Yukon and Northwest Territories and fire fighters have been trained to use these units from throughout the world including the US, Australia and African nations. We have been offering our rental fleet to California, Washington and Oregon through BC Wildfire Services and through direct communications with the Governor of California’s office but to no avail, as the US is not familiar, yet, with sprinkler protection on a large scale, which is common practice in Canada and to the best of my knowledge, Australia.

        Not to lay too much blame on CalFire, as they are crazy busy and bringing in new styles of equipment is not easy during an emergency. And to their credit, we were scheduled to provide demos of our SPU at the canceled WUI conference in Reno and officers from CalFire were scheduled to attend demonstrations of sprinklers, SPUs and other related equipment in May in British Columbia, but this event was also cancelled due to the Covid Crisis.

        There is a Case Study regarding the use of sprinklers during major wildfire event in British Columbia which you can find at:

        The study was prepared by FP Innovations in BC, which is a non-profit that produces information specific to forestry and the forestry industry in BC. The study speaks to gutter mount sprinkler brackets, which are manufactured and patented by Wasp. Again…not trying to produce an advertisement in this forum, so feel free to send me your email to rc******@wa**********.com and I will send you more info. We work with over 150 fire departments and Firesmart/Firewise communities in both the US and Canada (Firewise in the state of Georgia purchased over 50 of our gutter mount kits to distribute in Georgia) who provide our products to their community residents.

        In any case, British Columbia has literally tens of millions of dollars invested in sprinkler protection over the past decade and continues to increase the number of SPUs in the province. We have sold 18 Type 2 units to fire departments, contractors and first nations in BC over the past year a half alone. Sprinklers are front line proven in this province and the rest of Canada and I can provide dozens of fire hardened front line fire fighters that will attest to their effectiveness.


        1. Roof sprinklers are only viable where there is adequate water supply. For subdivisions in the WUI, a common problem is water pressure drops to nothing when many homes are watering and hydrants are being used for suppression. Don’t count on sprinklers working.

          For homes on wells, you can’t leave sprinklers running non-stop because it will run the well dry and burnout the pump motor so there’s no water even after the fire has passed. Also homes on wells require backup generators since losing power is common, so they are limited in run time by how much propane they have available.

          1. If I could, I would place as large a tank as possible (10k gal?) high enough to produce sufficient pressure at the discharge end and keep it full. Pumps can fail, as can power.

            Clyde, how do you address the wind issue?

          2. Hi Clyde, obviously every situation is different. Water is always a scarce commodity and must be used wisely. We only use agricultural grade sprinkler heads in our gutter mounts which have a 33′ spray radius and only use 1.5 to 2.5 gpm of water. These rotator heads are made by Nelson Irrigation in Washington State (Nelson R10T). They also work on very low pressure. The system can easily be placed on a simple timer available at most hardware stores to further conserve water. Many rural property owners will have back up generator power for the pumps required and separate water storage, built up over the winter can also assist in preparing for future wildfire events. When protecting dozens of homes off a hydrant line, the Incident Commander is making a decision on how much water they are using to prevent ignition vs how much is used to put out a home ingulfed in flames. It is common practice for Fire Chiefs in Canada to know the amount of water available at each hydrant and how fast the municipal system can recuperate water. I’m guessing US Fire Chiefs have this info at hand as well. For hydrant water use, we provide a simple valve in a portable case that runs off the fire hydrant. This Wasp in a Box can be programed for on off, straight on or off and water flow can be monitored from any cell phone anywhere on the planet. Again, water conservation is key and must be a priority, but there are ways available to do this that are not being utilized in most WUIs in the US and even Canada has room for improvement, as was demonstrated by the Fort McMurray fire of 2016 where over 2000 homes were lost.

  11. Maybe this isn’t the best place to ask this question, but since we are talking about house to house ignition, would it be appropriate for the fuel modeling folks to finally consider structures as a fuel model? I realize that there are currently 13 fuel models, but some folks generically refer to structures as the 14th.

    Perhaps if we added structures as a fuel model, future predictions could be more accurate and better aligned based upon threat.

  12. I am in no way a fire professional but, after the Oakland Hills Fire, i did research for the landscaping committee of the Mayors Firestorm Taskforce. That was a long time ago. I watched in horror as the Oakland Hills got rebuilt in the same old way, with almost no attention to the recommendations of our committee. Since then, I have lived in two California UWIs. In the more rural one, there were no rules at all, and people were actually allowed to walk away from active fires they had started to burn brush. In the other one, there were rules, but most homeowners and builders were more interested in saving money now, so they did their best to circumvent them. Maybe they knew about the huge settlements that allowed people in the Oakland Hills to build fancier houses than the ones they had before the firestorm.
    What I have also seen is houses that survived fires when others nearby didn’t. i was told by an involved firefighter that this was because they chose to defend what was defensible. If public policy is ignoring this fact, I am not surprised. Just sick at heart.

  13. I am a retired US Forest Service GIS specialist who lives in the Sierra Nevada foothills, so I have a personal interest in what will increase the chances of structure survival in a wildfire. I have been studying recent northern California fires with large structure losses, quantifying the pre-fire vegetation near structures, and tallying which structures survived and which did not. I used both CALFIRE’s post-fire structure inventory along with aerial photos to locate destroyed and surviving structures. My findings tend to support the point of this article. In three of the four fires I have studied, the Butte, Carr, and Camp fires, there appears to be a definite trend: the higher the vegetation cover near the structure, the higher the loss rate. For the Butte and Camp fires, for every increase in vegetation cover by 1%, the loss rate increased by 0.8%. For the Carr fire, the vegetation cover had a smaller effect. In the Carr fire, for every 1% increase in vegetation cover, the loss rate increased by 0.4%. The Tubbs fire did not exhibit the same relationship between vegetation cover and structure loss. In that fire there was a high loss rate across all vegetation cover classes. It may be the extreme winds in that fire (70mph+) simply overwhelmed the effects of vegetation cover near the structures.

  14. Some very interesting reading. Thanks for posting the article and comments. Over the years friends and family in fire prone areas have asked me to do informal fire risk assessments. In most of the cases I would simply say be prepared to leave early and quickly. There is a good chance you will lose your house/building.

  15. When it comes to ignition potential, one factor that has increased has been soil disturbance, which improves conditions for weed growth. The central plains were in balance and evolved with huge herds of migrating bison, which took some of the sweet, tender shoots and moved on. As the invading humans moved west, they killed off as man of the bison they could, busted the sod, and grew wheat, an annual grass that dried up at harvest time, to make “light bread.”

    They brought all sorts of annual alien weed grasses and forbs with them “by accident.” As they moved across the Rockies and into the Great Basin, they found grasses to be sparse, and the carrying capacity low. The concept of property came in, and the idea of “ownership” in common was largely abandoned. The land soon became too “cow-burnt” to support the stocking levels, due, ironically, to overstocking. What few native grasses were left took a back seat to, for example, the aptly monikered “cheat-grass.” Things haven’t changed much. Read J. Frank Dobie’s “Ceaser’s Meat” in the Atlantic Magazine, published sometime in 1965.

    So now to the point. Annual grasses that dry up every year make excellent tinder. More of it = more ignitions. And fast-spreading fires. With or without global warming, but every little bit hurts.

  16. Google tailspin r20 micro sprinkler…
    Conventional rainbird style sprinklers can be quite damaging to a structure, in addition to needing substantially more water to work. Most homeowners don’t have the water storage capacity or pump capacity to effectively use conventional sprinklers.
    I am familiar with micro style sprinklers from their use in our orchard for freeze protection. They put out a 360 degree spray of fine droplets.
    You can find them down to 1/3 gpm, which makes them very suitable for homes on limited water supplies.
    Used in conjunction with other fire proofing methods, I think they could be a very effective and affordable tool for home owners that want to be proactive about safeguarding their home/property.
    You don’t have to turn your house into a swamp..just a little bit of dampness everywhere to squelch those pesky embers would go a long ways…
    Just my 2 cents….

    1. Interesting. The important thing is that the embers are extinguished, and that means COVERAGE. My biggest worry is the effect of wind on sprinklers of any design. I’ve used impact-head sprinklers on my own house and was not happy with them throwing the water so high. Maybe with enough of those you suggest, one might be able to create a fail-safe system.

      While ANY coverage should help, I’d rather have redundancy rather than skimp. But one has to work with what one has–if you’ll pardon the expression!

  17. Agree that coverage is important. If you have that covered, the same wind(s) that drive embers are also going to carry all the fne water droplets to the same nooks and crannys that the embers lodge in.
    No system will be fail safe, but I am sure many can increase their chances exponentially….especially if they can stay and suppress what gets past their first line of defense. Before everyone gets their panties in a knot….I would suggest one only stay if they have the experience/training to do it safely and have a adaquate safety zone/hunker spot…
    Maybe Michele can direct some funding to do some mock up testing using a variety of sprinkler systems, keeping in mind that homes not on municipal water systems often have limited water supply. Our friend Randy from the north….but probably south of me at present…is dead on with the refrain that we can’t keep doing business as usual.
    I have been part of that business for over 40 years and the current system is not keeping up with the times. Fire suppression has it’s place, but in my opinion it’s oversold and hyped, both by the media and the agencies themselves..
    The poster who so adamantly defended “suppression” agencies was in my opinion just passing the buck. It is the suppression agencies who have the expertise and vested interest to take the seat at the head of the table on the issues of urban wildland fire (UWF)
    I live outside any incorporated area and there are no codes or requirements. I have a pretty fair idea of my exposure and what I need to do, but I guarantee you 90% of my neighbors don’t….you can tell that by just looking at their properties.
    Yet they are under the illusion that teams of firefighters are coming to the rescue when the smoke is rolling and embers are hitting the roof….not likely to happen
    It’s mostly that, that gets under my skin….I would like to see these fire management folks be a lot more honest with the public about the limitations of their suppression capabilites. That means telling people maybe what they don’t want to hear, and putting a lot of the resposibility where it really lies….on the home owner. But many of these home owners need help figuring it out, and maybe even getting it done..such as a senior citizen on a fixed income…local firefighters could spend a few shifts helping thin and limb and give a hand or advice.

  18. I feel that much of the literature and narratives about the WUI put the responsibility on the homeowner. I have not seen data to warrant such conclusions; yes, there are papers, but where exactly can other scientists find and examine the data that folks have used to come to these conclusions.

    One crucial missing item from studies that have concluded these things is defensive actions (I am not saying the responsibility is solely on the first responder. Yes, they are often evacuated during the passage of the wildland fire front). There are virtually no scientific studies that account for the consequences of defensive actions in terms of building response at WUI fires. Consequently, we do not know what will happen without first responders or homeowners defending these homes, and we have some evidence that implementing defensible space helps folks protect homes. Recent large fires in Oregon, the Camp Fire, the Tubbs Fire, point to home destruction not stopping without first responders’ aid. I have not seen any studies or any data to indicate that any WUI mitigation advice is effective without first responders defending against the fire, stopping major structure-to-structure fire spread (typiically after exposures are lower due to changing weather, etc.), etc. Once one home ignites in a high-density area, or perhaps even moderate density, the WUI mitigation advice is potentially no longer effective, I feel.

    As an analogy, imagine you were testing the effectiveness of a new drug for cancer. Imagine this assessment did not consider other treatments such as chemo, radiation, and surgery. The drug could be deemed effective when, in reality, it would not be effective without these other treatments. Another essential item to consider in post-fire assessments is exposure. Almost all studies from which this information was derived, seem to have the same unstated assumption that all homes received the same exposure. This is not the case in WUI fires.

    I think the path forward is the ubiquitous sharing of information and data. Scientists need to publish and share all their data, not just papers and reports. Homeowners need to document conditions on their property pre-fire also, so we can assess post-fire. Everyone has to publish and share their data. We are all in this together, homeowners, wildland property owners, authorities having jurisdiction, scientists; it is all of us together that will address this problem.

    I encourage scientists who have conducted such studies to publish the data from which their conclusions were derived (I can find no such data). Then future generations can build from previous work, identify shortcomings, and continue the scientific endeavor. Without the data, the next generation will be faced with the same problem as my generation: a lack of co-located, quality-assured, and documented to 21st century standards post-fire data to describe and be able to review the respective scientific effort regarding the WUI.

    I very much appreciate Dr. Cohen’s and others’ early efforts in the WUI. They have certainly contributed a great deal. I urge all homeowners to implement the current advice provided to them. However, I do not believe we have it all figured out. Significant study and work are required to address this problem and see if additional mitigation treatments are required beyond what is currently recommended. After all, neighborhoods that are FIREWISE burn to the ground (Fountain Grove at the Tubbs Fire where there were no first responders because they were overwhelmed fighting the fire everywhere else), so clearly the suggested advice does not always work (this does not mean homeowners should not implement the advice), and maybe defensive actions are a key component to pre-fire WUI treatments being effective.

  19. Well here we go…I’m a 30 year veteran of initial attack and structure protection during wildfire events. I’m also the inventor of our patented and worldwide patent pending Gutter Sprinkler Kit that is homeowner deployable. I guess I’m in the middle on all the discussions on what works and what doesn’t. I read how home owners are looking for advise and some direction on the best possible chance to save their home during an interface fire. I’ve read documents published by our most respected wildfire scientists and researchers advising about defensible space and how to create that. On that point I agree 100% on creating an ignition free zone around your home and just as important your out buildings as well.

    No matter how I express my opinion and feelings on this very sensitive and personal
    subject I do not want nor intend this to be anything but what I have read and personally saw during my career. This is not a commercial for our products either. Bottom line is that with a couple of hundred dollars investment for sprinklers with low gallons per minute water consumption that are easily deployed during a wildfire evacuation, the chances of a home surviving goes up dramatically. There are arguments that any available water in a subdivision needs to be available to our first responders so they can take a tactical response home by home to defend against loss.
    There lies a problem as our very dedicated and brave first responders do not have the man power or equipment to respond to an entire subdivision at risk from an advancing wildfire, so gear up some sprinklers and get out. A simple $25 water timer attached to a gutter sprinkler can be set to come on and off just enough to wet the roof and surrounding area down making water consumption minimal. This is where most ember attacks destroy homes. Agricultural grade sprinklers are state of the art in that they have been designed to put water where it is intended even during high wind situations. If anything, wind has a tendency to distribute water, thus wetting down larger areas raising humidity and lowering ignition potential.

    This fight against a home owner losing their life long investment and belongings to wildfire is personal as my wife and I have family who have experienced loss due to an interface fire. No amount of money can replace lost lives, homes, memories, personal effects etc…

    We have a vast data base and product range for residential and commercial wildfire protection available to anyone wanting to learn more on how and when to deploy counter measures to dramatically increase survivability of structures.

    Everyone, please stay safe
    Darrell Pyke

    1. Darrell,

      I would like to get a copy of the database used to derive your conclusions. Please send to dm***@gm****.com

      Derek McNamara,
      Geospatial Measurement Solutions, LLC

    2. I pitched your general approach after working with a fire hazard reduction task force following the Kitchen Creek (Laguna Mountain) Fire in 1970. I got the idea by researching the literature and found (pre-Internet) that an Australian had built a 6k gallon (Imperial?) tank, with an electric start (battery) pump (250 gpm @ 90psi) and an exterior steel pipe system of his own design, plus thermocouples placed out in the bush to activate the system automatically. I couldn’t “sell” the idea, but I still believe that an excellent automatic and remote-controlled suppression system is the best approach. A friend who built a house following all of the “fireproofing” building codes still lost it.

      ALL structures in a subdivision must have it, because a structure fire is far more hazardous than a brush fire. Ask Jack Cohen what he found after the Cedar Fire in 2003.

  20. CALFIRE does send out teams to record characteristics of structures that have burned and records those characteristics in the Damage Inspection (DINS) database. In 2018, they began to include information on what structures had been defended. The data is often incomplete, however, because building characteristics are hard to determine when the structure is destroyed. And usually there is little or no information recorded on buildings that survived the fire with no damage. So it is difficult to use the database to compare houses that burned with those that did not. Insurance companies likely have good data on housing characteristics, but that is considered proprietary and is not available for research purposes. And no one gathers data on those “micro” conditions that can lead to home ignition: pine needles in the gutters, firewood stacked next to the house, etc. In any case, no home protection strategy is going to completely eliminate the losses in wildfires. In the Tubbs fire, for example, 80% of the structures within 50 feet of a burned area were either destroyed or received major damage. That means the fire likely destroyed many houses where all guidelines had been followed. 70mph winds can negate all attempts at reducing fire risk.

    1. Unfortunately, identifying building and landscape conditions in post-fire WUI environments is at least partly an exercise in futility, as you say. I recommend homeowners document their property’s building and landscaping characteristics before the fire (this is a good exercise for insurance claims anyway) if local authorities cannot (sometimes they do also).

      Here is a paper I wrote on indicators of defensive actions that folks can use from the field and air to identify defensive actions:

      A big indicator that inspectors sometimes miss is damaged homes. As Dr. Cohen’s work has identified, and this has been substantiated at several other WUI fires, a damaged home is typically defended, maybe not always, but that is the best assumption lacking additional information, in my opinion.

      Finally, damage inspections would be improved, in my opinion, if they documented the specific building component(s) damaged (e.g., eave, deck, roof, etc…). I recommend performing this type of documentation instead of figuring out building characteristics of a destroyed building (this might be unsafe anyway due to toxic debris). A damaged building that was extinguished can provide evidence of building vulnerabilities.

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