tag:theconversation.com,2011:/ca/topics/california-fire-2017-45193/articlesCalifornia fire 2017 – The Conversation2017-12-13T11:25:11Ztag:theconversation.com,2011:article/888252017-12-13T11:25:11Z2017-12-13T11:25:11ZCalifornia needs to rethink urban fire risk, starting with where it builds houses<figure><img src="https://images.theconversation.com/files/198860/original/file-20171212-9389-1ujygzj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This fire season has been particularly damaging to urban areas.</span> <span class="attribution"><span class="source">AP Photo/Reed Saxon</span></span></figcaption></figure><p>Wildfires raging across southern California are causing evacuations of many communities and have destroyed <a href="http://www.latimes.com/local/lanow/la-me-ventura-fire-20171206-story.html">hundreds of structures</a> this month. </p>
<p>These fires follow the wind-driven Tubbs fire earlier this fall that blasted through densely urbanized neighborhoods in Northern California, causing dozens of fatalities and thousands of home losses. Stories from both fires of how fast the fire spread and how little time people had to evacuate are stunning. </p>
<p>With widespread damage to structures, these fires highlight the importance of where and how we build our communities and, in particular, how land use planning and better building codes can reduce our exposure to such events.</p>
<p>Despite how unusual the devastation appear in portions of these fires, we need to recognize that these structure-to-structure “urban conflagrations” have happened in the past and will happen again. Yet these fires revealed that we have key gaps in our policy and planning related to assessing risk in fire-prone environments.</p>
<p>What is increasingly clear to fire researchers <a href="http://ucanr.edu/?facultyid=1595">like me</a> is that losses on the human side are often driven by where and how we build our communities. This means we must <a href="https://www.americanscientist.org/article/coexisting-with-wildfire">learn to coexist with fire</a>, if we are going to inhabit fire-prone landscapes, just as we adapt to other natural hazards. An essential step is to shift our perspective from a focus on hazard to one that more comprehensively includes human vulnerabilities.</p>
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<a href="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The devastation from the Tubbs fire earlier this year. An urban fire that gave many people little time to leave points to the need for better planning on evacuation.</span>
<span class="attribution"><span class="source">AP Photo/Marcio Jose Sanchez</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Mapping risk</h2>
<p>California is leading the way in mapping the danger that wildfires pose to human communities and, in particular, linking building codes to fire severities that may be expected in given location. The state’s <a href="http://www.fire.ca.gov/fire_prevention/fire_prevention_wildland">Fire Hazard Severity Zone maps</a> are an essential step in recognizing fire as an inevitable process that must be accommodated, similar to how we plan for floods, landslides, earthquakes and hurricanes.</p>
<p>What is missing from these maps, however, is extreme weather patterns. The <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009GL041735/full">Santa Ana winds</a> of Southern California are a notable example. Strong, hot and dry wind episodes are associated with nearly all of our largest and most destructive wildfires, including the <a href="http://napavalleyregister.com/calistogan/news/local/tubbs-fire-reminds-locals-of-hanley-fire-of/article_dce8464f-1557-5956-a508-04fffe8d7043.html">1964 Hanley fire in Northern California</a> that burned an almost identical footprint to the Tubbs fire, yet relatively little is currently known about how often they occur across a landscape. </p>
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<a href="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Updating maps on fire risk should inform urban development.</span>
<span class="attribution"><span class="source">Cal Fire</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>New methods are becoming available for mapping and modeling winds, and future versions of the Fire Hazard Severity Zone maps will therefore include such weather conditions. Similar maps are also needed for fire-prone areas outside California.</p>
<p>Despite technical advances, a key problem with most mapped approaches to fire danger is that the focus is almost exclusively on characterizing the hazard – flame lengths, rates of spread or fire intensities of an oncoming wildfire – and much less on the vulnerabilities of what is actually exposed. The “<a href="http://silvis.forest.wisc.edu/maps/wui">wildland-urban interface</a>,” where developed lands are exposed to natural, flammable areas, is thus often mapped and assumed to be where the exposure ends.</p>
<p>Clearly this is not always the case. Analogous to when a levee fails, after a wildfire manages to ignite homes along the wildland-urban interface, many homes farther inside the neighborhood can quickly become exposed.</p>
<p>Depending on the building codes in place during their construction, these newly exposed structures may or may not be very fire-resistant. Their vulnerability to ignition can also be especially high if they are spaced closely together and the winds are strong, because that is when fire spread transitions to a structure-to-structure domino effect.</p>
<p>Better fire risk mapping means we should be able refine our notion and approach to assessing vulnerability.</p>
<h2>Reducing human exposure</h2>
<p>There are numerous reports of how difficult and deadly it was <a href="http://www.mercurynews.com/2017/10/09/santa-rosa-fire-how-a-sudden-firestorm-obliterated-a-city/">to evacuate during the Tubbs fire</a>. Apparently many people had almost no warning at all. This highlights the importance of both evacuation planning and evacuation communication systems, as getting out in time is what Americans tend to rely on in wildfire situations.</p>
<p>Although evacuation preparedness is nearly always mentioned in <a href="http://www.firewise.org/usa-recognition-program/cwpps.aspx">Community Wildfire Protection Plans</a> and <a href="http://www.readyforwildfire.org/Go-Evacuation-Guide/">standard guidance for home owners</a>, the overriding message is typically to “leave early” whenever possible.</p>
<p>While absolutely correct, this advice minimizes the importance of pre-fire evacuation planning and the short time there may be to get out. It takes quite a bit of thought and effort to anticipate being in such a crisis situation!</p>
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<img alt="" src="https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198897/original/file-20171213-31699-1avj8xc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Fleeing fire in Ventura, California.</span>
<span class="attribution"><span class="source">AP Photo/Noah Berger</span></span>
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<p>What should one take, and where might one actually go?</p>
<p>On short notice, how does one account for pets, children or the elderly?</p>
<p>Is there a place one should retreat to, if evacuation orders are received too late or not at all?</p>
<p>This last question may be the one that gets the least attention, and the many fatalities in the Tubbs fire suggest that it requires much deeper consideration. Firefighters are often given <a href="https://www.nifc.gov/wfstar/downloads/safety_essays/Alexander_VICFFR_keynote_address.pdf">specific training</a> about what to do with limited evacuation options. For homeowners, however, <a href="http://www.readyforwildfire.org/What-To-Do-If-Trapped/">guidance can be sparse</a>.</p>
<p>When it is too late and too dangerous to evacuate safely, fallback options must be considered and communicated ahead of time. In an urban conflagration situation, local details dictate whether “<a href="http://firesafemendocino.org/creating-a-safety-zone-for-use-in-a-wildfire-emergency/">safety zones</a>” actually exist as places to take refuge. Given the real potential for such disasters, many communities should consider identifying (or building) key “hardened” structures to act as local-scale refuges.</p>
<p>Reducing human exposure involves more attention to what people must do during a wildfire, or even the rare urban conflagration. Safe evacuation deserves as much emphasis as reduction of fuels, such as creating defensible space around homes or larger scale fuel breaks by thinning vegetation around communities. </p>
<h2>A safer built environment</h2>
<p>From the scale of individual home construction up to the location and arrangement of development on a landscape, our communities should be better able to survive the natural hazards that occur there. This requires both short- and long-term strategies for achieving a safer built environment.</p>
<p>As a starting point, we must acknowledge that we currently have tens of thousands – possibly even hundreds of thousands – of homes constructed according to building codes that leave these structures vulnerable to ignition. Amazingly, however, there are very few <a href="http://thinisin.org/index.php/structural-ignitability/replacing-wood-roofs">examples of grant programs</a> to mitigate such vulnerabilities through retrofit programs to, for instance, replace wood shake shingle roofs or to upgrade attic and crawlspace vents to block embers from entering homes.</p>
<p>In contrast, there are millions of dollars in public funds spent annually on community-scale fuel reduction projects. These are common activities pursued by <a href="http://www.cafiresafecouncil.org/">Fire Safe Councils</a> in California and similar organizations in other states.</p>
<p>The same level of support should be available for mitigation of fire-related structure vulnerabilities as there is for hazards.</p>
<p>Over the long term, land use planning is probably the most effective tool available for creating safer communities. We must be more deliberate about how we develop on fire-prone landscapes, taking advantage of emerging hazard-mapping techniques.</p>
<p>The goal here is not necessarily to build fewer homes, but to design and site developments that avoid the highest hazard regions and concentrate development in the lowest hazard areas. This logic applies, to varying degrees, to constraining development with respect to other natural hazards.</p>
<p>Despite an aversion by some to land use planning, this strategy is simply common sense. It will also save lives and massive amounts of public resources over the long term.</p>
<p>Where we do choose to develop and inhabit hazard-prone environments, it may be necessary to design communities with “<a href="https://www.buildinggreen.com/op-ed/passive-survivability">passive survivability</a>” in mind, or the ability to withstand the event and have water and power for a few days. This provides both the built environment and the people within some basic protection for a limited time. </p>
<p>Strategies exist to lower the risk of fire in the current housing stock and to more carefully design and site future development where wildfires are possible. With increasing <a href="https://theconversation.com/wildfires-in-west-have-gotten-bigger-more-frequent-and-longer-since-the-1980s-42993">extremes expected</a> as climate continues to change, <a href="https://theconversation.com/why-hurricanes-harvey-and-irma-wont-lead-to-action-on-climate-change-83770">officially recognizing this link</a> and creating a safer built environment will only become more urgent.</p>
<p><em>This is an updated version of an <a href="https://theconversation.com/california-needs-to-rethink-urban-fire-risk-after-wine-country-tragedy-85966">article</a> originally published on October 23, 2017.</em></p><img src="https://counter.theconversation.com/content/88825/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Max Moritz has received funding from Federal (e.g., NSF, USFS) and California State (e.g., CEC, CalFire) sources.</span></em></p>With wildfires continuing to rage across southern California, a fire researcher says lowering fire risk means reconsidering where and how we build our communities.Max Moritz, Cooperative Extension Specialist, Wildland Fire, University of California, Santa BarbaraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/888172017-12-08T02:58:47Z2017-12-08T02:58:47ZCalifornia fire damage to homes is less ‘random’ than it seems<figure><img src="https://images.theconversation.com/files/198202/original/file-20171207-11315-1ygt36d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can California update its building codes to minimize fire damage?</span> <span class="attribution"><span class="source">AP Photo/Jae C. Hong</span></span></figcaption></figure><p>In the midst of the many <a href="http://www.latimes.com/local/lanow/la-me-ln-school-fire-20171204-story.html">wildfire</a> <a href="http://www.pressdemocrat.com/news/7588914-181/cal-fire-4658-homes-destroyed?gallery=7597510&artslide=0">emergencies</a> that have <a href="https://www.sfchronicle.com/bayarea/article/Cal-Fire-Thomas-Fire-in-Ventura-County-12407361.php">faced California</a> this year, it can often seem that the way houses burn, or don’t, is random. </p>
<p>The thing is, though, it’s not. Firefighters and researchers alike have a pretty solid understanding of why some houses are more vulnerable to wildfire than others. The real challenge ultimately lies in whether those with the power to act on that knowledge will do so.</p>
<h2>Available science</h2>
<p>It is commonly thought that it takes direct flame to spread a fire, but this isn’t always the case. Small embers are instead often the <a href="http://iopscience.iop.org/article/10.1088/1748-9326/4/1/014010/pdf">culprits that begin house fires</a> during wildfires. These small bits of burning debris can be lofted long distances by the wind. They can then end up igniting landscaping materials like combustible mulch, or enter homes through vulnerable spots – gutters teeming with debris, unscreened attic <a href="http://firecenterbeta.berkeley.edu/housedemo/vents/t6-v1.html">vents</a>, open or broken <a href="http://firecenterbeta.berkeley.edu/housedemo/windows/t25-w1.html">windows</a>, old <a href="http://firecenterbeta.berkeley.edu/housedemo/roof/t8-r1.html">roofs</a> with missing shingles. Once there, the embers smolder and can ultimately catch a house on fire.</p>
<p>In California, <a href="http://www.cnn.com/2017/12/06/weather/santa-ana-winds-explained/index.html">iconic winds</a> work to create ideal ember-driven ignition conditions. The Santa Ana winds in Southern California – known as the Diablo winds in northern part of the state – have generally followed fairly predictable seasonal and spatial patterns. <a href="http://calfire.ca.gov/communications/communications_firesafety_redflagwarning">“Red flag” fire warnings</a> are often issued on dry days when the winds will be particularly fierce.</p>
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<a href="https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198201/original/file-20171207-11318-1oldt5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Avoiding fire on Highway 101 north of Ventura, California.</span>
<span class="attribution"><span class="source">AP Photo/Noah Berger</span></span>
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<p>While humans <a href="https://baynature.org/article/californias-massive-fires-break-illusion-control-disasters/">can’t really control</a> as much as we’d like to believe when it comes to disasters, we do have the ability to control where and how we build. For decades, most wildfire education and enforcement campaigns have focused on creating so-called <a href="http://www.readyforwildfire.org/Defensible-Space/">defensible space</a> where landscaping vegetation is carefully selected and located on the property, as well as routinely maintained. </p>
<p>This is not enough, however. Officials in California – as in other fire-prone states – need to help <a href="http://firecenter.berkeley.edu/toolkit/homeowners.html">homeowners</a>, <a href="http://ucanr.edu/sites/cfro/Fire_Information_Toolkit/Community_Leaders/">local governments</a> and <a href="http://firecenterbeta.berkeley.edu/bwmg/">builders</a> to understand there are also specific, science-based steps that can be taken to make <a href="http://firecenterbeta.berkeley.edu/housedemo/">structures themselves less vulnerable to fire</a>. </p>
<p>Researchers recommend what is known as a “coupled approach” to home and building survival. This means the development and maintenance of an effective defensible space, as well as the careful selection of <a href="http://firecenterbeta.berkeley.edu/bwmg/">construction materials</a> and correct installation to ensure that, for example, there are not gaps in siding or roofing that would allow embers to penetrate.</p>
<p>Decision-makers also need to be willing to take on the most taboo topic of them all: recognizing that there are places houses simply <a href="https://theconversation.com/california-needs-to-rethink-urban-fire-risk-after-wine-country-tragedy-85966">shouldn’t be built, or rebuilt, at all</a>. </p>
<h2>(Not) too urban to burn</h2>
<p>Earlier this year, California had the <a href="https://www.nytimes.com/2017/04/07/us/california-drought.html">first strong winter rains</a> after many years of drought. Now, after a typically dry summer, the state is experiencing a <a href="https://www.theverge.com/2017/12/6/16742496/california-la-ventura-thomas-rye-creek-fires-drought-water-climate">dry start to the rainy season</a>, particularly in the south. At the same time, people have continued to build into places known to burn regularly. The result of this confluence of events has been fires deeply affecting many thousands of people up and down the state.</p>
<p>California residents are largely aware that not all fire is bad, and that many of our ecosystems thrive on regular fire. It’s not something that we should, or ever could, hope to fully contain. Our only chance is learning, really and truly and finally learning, <a href="https://theconversation.com/learning-to-live-with-wildfires-how-communities-can-become-fire-adapted-59508">to live with it</a>.</p>
<p>In that vein, the state must look long and hard at some of the steps that have been the hardest to take – not building in places that are particularly fire-prone and matching building codes with a modern understanding of wildfire risk – if there is to be any hope of alleviating the human suffering these fires cause.</p>
<p>We are being invited to free ourselves from the notion that wildfire destruction is random and unpredictable, and that therefore there is nothing to be done about it. As the fire season in California <a href="http://www.latimes.com/projects/la-me-california-fire-seasons/">gets longer</a>, the <a href="https://www.citylab.com/environment/2017/12/los-angeles-is-burning-again-and-again/547637/">winds worsen</a> and wildfires move into areas once deemed too urbanized to burn, maybe the knowledge about what makes houses burn can finally be put to good use.</p><img src="https://counter.theconversation.com/content/88817/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Faith Kearns does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are well-understood ways to minimize the risk of fire spreading through housing – if only developers, homeowners and officials took heed.Faith Kearns, Academic Coordinator, California Institute for Water Resources, University of California, Division of Agriculture and Natural ResourcesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/860432017-10-27T10:19:19Z2017-10-27T10:19:19ZWhy were California’s wine country fires so destructive?<figure><img src="https://images.theconversation.com/files/191970/original/file-20171026-28071-hc4dhy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Burned area in Santa Rosa, California, Oct. 11, 2017.</span> <span class="attribution"><a class="source" href="https://www.defense.gov/Photos/Essay-View/CollectionId/17453/">US Department of Defense</a></span></figcaption></figure><p>As of late October more than a <a href="http://google.org/crisismap/google.com/2017-tubbs-fire">dozen wildfires</a> north of San Francisco had <a href="http://www.latimes.com/local/lanow/la-me-ln-fires-20171018-story.html">killed more than 40 people</a>, burned approximately 160,000 acres and <a href="http://calfire.ca.gov/communications/communications_StatewideFireSummary">destroyed more than 7,000 structures</a>. </p>
<p>This tragic loss of life and property is unprecedented in California. However, the fires are not anomalous events in terms of their size, intensity or the speed with which they spread. Indeed, the path of the destructive <a href="http://www.fire.ca.gov/current_incidents/incidentdetails/Index/1867">Tubbs fire</a> in Napa and Sonoma counties mirrors that of the <a href="http://www.sfchronicle.com/thetake/article/Wine-Country-fire-of-1964-Eerie-similarities-to-12267643.php">Hanley fire of 1964</a>. This extreme wind-driven fire burned under similar conditions, across much of the same landscape and covered an area substantially greater than the recent Tubbs fire. </p>
<p>Strikingly, though, no lives were lost during the Hanley fire and only 29 structures were destroyed. Why did these two fires, 50 years apart, burn on the same general landscape, under similar extreme winds, with such different human impacts? Fire scientists will study these events intensively to parse out the relative importance of various factors. But it is clear that two factors probably were major contributors: wind and population growth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=444&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=444&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=444&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=558&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=558&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191961/original/file-20171026-28030-1j42pgu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=558&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">California wildfires photographed from space on October 9, 2017.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/goddard/2017/wildfires-running-amok-in-california">NASA Earth Observatory</a></span>
</figcaption>
</figure>
<h2>Driven by Diablo winds</h2>
<p>The Tubbs fire began on the night of Oct. 8 near Calistoga in Sonoma County under extreme fire weather conditions, with high winds and low relative humidity. Normally, winds in this region flow from the west, carrying cool, humid air from the ocean onshore. These winds reversed that pattern: They blew out of the northeast at 40 miles per hour, with gusts up to 75 miles per hour. Such winds are common in California during the autumn, and are known as Diablo, Mono or North winds in Northern California and Santa Ana winds in Southern California. </p>
<p>These hot, dry winds develop from an unusual pattern of high and low pressure cells, and are most prominent in autumn. They follow the normal summer and fall drought that occurs in this Mediterranean-type climate, leading to severe fire weather conditions. Such winds are associated with some of the most catastrophic fires in California’s history. In the San Francisco Bay area, they played a role in the <a href="http://ggweather.com/firestorm/1991OESreport.pdf">1991 Tunnel fire</a>, where wind gusts of 60 miles per hour were responsible for 25 deaths, even though the fire measured only slightly over 1,000 acres. The speed of these fires is a major factor leading to the loss of human lives. </p>
<p>Since fires in Northern California do not appear to have changed in this 50-year period, what accounts for the difference in impact? Certainly one critically important factor is demography. California’s population has <a href="https://www.statista.com/statistics/206097/resident-population-in-california/">more than doubled</a> in the past 50 years, but Santa Rosa, which was hit hard by the Tubbs fire, has five times as many people as it did in 1964.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=253&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=253&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=253&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=317&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=317&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191457/original/file-20171023-1698-7xwnvr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=317&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Population growth in Santa Rosa, California.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Santa_Rosa,_California#cite_note-DoF-28">CA Dept of Finance</a></span>
</figcaption>
</figure>
<h2>Population growth</h2>
<p>This dramatic growth can affect fire losses in several ways. Nearly all fires in Sonoma County are caused directly or indirectly by people, such as intentional ignitions or power lines igniting fires. Population growth raises the probability of fire igniting under severe weather conditions. More frequent human-caused fires also convert woody vegetation to more abundant herbaceous vegetation, which <a href="https://d2k78bk4kdhbpr.cloudfront.net/media/publications/files/Halsey_and_Syphard_High_Severity_Fire_in_Chaparral_20151.pdf">increases ignition probability and the rate of fire spread</a>. </p>
<p>Population growth also spurs urban expansion. Development has spread outward, positioning <a href="https://theconversation.com/dont-blame-california-wildfires-on-a-perfect-storm-of-weather-events-86128">people closer to watersheds of dangerous fuels</a>. These fires burned through grasslands, oak woodlands and dense stands of <a href="http://www.californiachaparral.org/">chaparral</a> shrublands that last burned 50 years ago. Diablo winds are often funneled by <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009GL041735/full">particular topographic features</a>, such as low-lying passes in mountains. This makes some parts of the landscape, which fire experts refer to as wind corridors, more vulnerable than others. </p>
<p>The so-called wildland-urban interface, or intermix, where development and wildland vegetation meet, is <a href="http://silvis.forest.wisc.edu/maps/housing">where most homes are destroyed by fires</a>. Data presented at a <a href="https://vimeo.com/238751761">recent Senate Science Forum</a> show that both high- and low-density development in the areas where the California wine country fires occurred have expanded dramatically in the last several decades.</p>
<h2>What about climate change?</h2>
<p>Many accounts increasingly see climate change as a <a href="http://www.laweekly.com/news/study-probes-connection-between-climate-change-fires-8766855">contributing factor</a> in big fire events. There is good evidence that climate change will increase fires in some western forests, but there is little evidence that it will play a similar role in coastal California. </p>
<p>In a <a href="http://www.publish.csiro.au/WF/WF16102?jid=WFv26n4&xhtml=BE6E3DBA-8037-4C1E-BB01-C05C107B0578">recent study</a>, we examined over 100 years of California climate records and examined the extent to which higher temperatures in different seasons might have contributed to enhanced fire activity, and found that there was very little correlation in coastal California. We hypothesized that this was likely because in lower elevations, temperatures are sufficient to lead to large fire events in most years, and fires are more strongly controlled by the timing of human ignitions in association with extreme winds. </p>
<p>Some reports have suggested that widespread tree deaths helped fuel the recent firestorm. The <a href="http://dx.doi.org/10.1002/2015GL064924">extreme drought of 2012-2014</a> caused extensive tree deaths, but most mortalities occurred farther east, in California’s Sierra Nevada mountains. In coastal counties, in contrast, many trees have been killed by <a href="http://www.sfgate.com/bayarea/article/Sudden-oak-death-likely-exacerbated-deadly-12292099.php">sudden oak death syndrome</a>, a disease spread by an exotic fungal pathogen. </p>
<p>However, according to the California State Tree Mortality Database, there were <a href="http://egis.fire.ca.gov/TreeMortalityViewer/">few dead trees within the fire perimeters</a> in wine country. And in some instances fierce winds carried the fire to communities that were a mile or more away from dangerous wildland fuels such as dead trees. These facts imply that tree mortality played a minimal role in the destruction caused by this firestorm. </p>
<p>Still another potential factor is above-normal rainfall during 2017. High rainfall increases plant growth in grasslands, which leads to increased fire incidence and spread. In all likelihood this did play some role. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191967/original/file-20171026-28033-pksy5c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sign at a residence in the hills above Sonoma, California alerts people to an available pool if needed to shelter from wildfires, Friday, Oct. 13, 2017.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/California-Wildfires-One-Day/ef8f429cd73c49cf94083e2f26fdd189/240/0">AP Photo/Ellen Knickmeyer</a></span>
</figcaption>
</figure>
<h2>Human factors</h2>
<p>Looking to the future, <a href="https://doi.org/10.1071/WF16102">fire-climate studies in coastal California</a> have concluded that in this coastal region, direct human impacts are likely bigger concerns than indirect impacts from climate change. </p>
<p>On the plus side, this suggests that there is great potential for altering fire outcomes by reducing fire ignitions. We do not yet know what ignited this year’s Northern California fires, but extensive experience within the state points to several likely culprits: downed power lines, arson, debris burning and equipment such as generators. </p>
<p>Since these fires started at night, debris burning and equipment seem to be less likely causes. However, there were <a href="http://www.mercurynews.com/2017/10/12/california-fires-pge-power-lines-fell-in-winds-that-werent-hurricane-strength/">reports</a> of extreme winds blowing down power lines, and historically such events have started some of California’s worst fires. </p>
<p>Current U.S. Geological Survey research indicates that during the last several decades there has been a significant decline in arson-ignited fires in California and a decline in area burned due to arson. In all likelihood, increased fire prevention strategies have played a role in this decline. On the other hand, power line fires have not declined in number or area burned in the last several decades, and ignitions from power lines remain a statewide problem. Actions that can reduce the risk of this ignition source can include <a href="https://www.werc.usgs.gov/ProductDetails.aspx?ID=3987">placing power lines underground</a>.</p>
<p>Drought and warmer climates have made wildfires <a href="https://ca.water.usgs.gov/wildfires/index.html">a year-round hazard</a> in California. Expanded urban development, in tandem with hot winds, seems to be the primary reason for the destruction this year. Once we better understand what factors made the 2017 fires so damaging, <a href="https://theconversation.com/california-needs-to-rethink-urban-fire-risk-after-wine-country-tragedy-85966">communities can prepare</a> for future outbreaks in this increasingly fire-prone landscape.</p><img src="https://counter.theconversation.com/content/86043/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jon Keeley is affiliated with the U.S. Geological Survey and the University of California, Los Angeles</span></em></p>Fire is part of the ecology in much of California, but recent wildfires have caused much more damage than past burns of similar size. A fire ecologist points to two key factors: winds and population growth.Jon Keeley, Research Ecologist, US Geological SurveyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/861282017-10-25T23:38:58Z2017-10-25T23:38:58ZDon’t blame California wildfires on a ‘perfect storm’ of weather events<figure><img src="https://images.theconversation.com/files/191888/original/file-20171025-25518-1e5zh2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In explaining the causes of wildfires, the media and policymakers typically point to environmental factors, but that's not the whole story.</span> <span class="attribution"><span class="source">AP Photo/Marcio Jose Sanchez</span></span></figcaption></figure><p>Late evening on Oct. 8, a series of fires ignited in Northern California’s famous Wine Country region. The fires would produce the most damaging wildfire event in California’s history. Forty two people died and over <a href="http://www.latimes.com/local/lanow/la-me-wildfires-devastation-20171023-story.html">8,000 structures were destroyed</a>. </p>
<p>As the fire threatened new neighborhoods, media reports filled airwaves and front pages across the nation, with most coverage conveying a mix of compassion, grief, anxiety and disbelief. And as usual, diverse groups began trying to explain the severity of this most recent wildfire disaster by referencing a unique confluence of environmental factors, such as high temperatures, strong winds, and lots of vegetation available as fuel.</p>
<p>But having researched the intersection of urban development and fire in the western U.S., including the <a href="https://www.ucpress.edu/book.php?isbn=9780520292796">1991 Oakland Fire</a>, I’ve come to see how flawed this way of looking at fires is. Calling wildires a result of a “perfect storm” is highly simplistic and arguably dishonest. It ignores the long and complex social-ecological fuse that actually leads to costly and injurious wildfire disasters. </p>
<h2>The narrative of unruly natures</h2>
<p>A <a href="http://www.cnn.com/2017/10/11/us/northern-california-fires-factors/index.html">news article</a> from CNN published on Oct. 11, roughly three days after the Wine Country fires first ignited, nicely captures the widely accepted explanation circulated within media outlets. </p>
<p>The article described four factors that could explain the size and destruction of this wildfire. First, strong and dry easterly winds whipped across the landscape just as the fire ignited. Second, three of the largest fires began as residents were headed to bed, thus delaying emergency responses. Third, an accumulation of dead vegetation around homes from protracted drought conditions and mountain pine beetle infestations resulted in landscapes that were particularly susceptible to ignition from flying embers. And fourth, the fire erupted during a low humidity time of year, and after many months without rainfall. According to this CNN article, these four dynamics converged to created “a perfect storm of factors” that fanned the wildfires and contributed to their size, magnitude and ferocity. </p>
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<p>Another <a href="https://www.newscientist.com/article/2150068-californias-wildfires-powered-by-perfect-storm-of-fire-hazards/">news report</a> from the same day titled, “California’s wildfires powered by a perfect storm of fire hazards” added the role of climate change to the disaster-making equation, noting that rising temperatures are increasing fire hazards across the region. </p>
<p>As these accounts suggest, the “perfect storm” narrative connotes a unique alignment of conditions that are both surprising and out of our control. It implies the convergence of unusual, unforeseen and unavoidable circumstances. </p>
<p>There are two major problems with this brand of story telling. </p>
<p>The first problem involves what factors get included – and excluded. Nearly always, the drivers of wildfire disasters referenced by the media and government officials are environmental. These include <a href="http://www.scientificamerican.com/article/how-the-u-s-west-can-live-with-fire/">statements</a> such as “drought and heat wrought by stubborn ocean conditions have left great stretches of [the American West] dryer and more combustible than usual this year,” or <a href="http://www.theblaze.com/news/2016/06/25/massive-wildfire-rages-in-california-at-least-2-dead-150-homes-destroyed/">reports</a> that dangerous fire activity is the result of “scorching heat and tinder-dry conditions across the West.”</p>
<p>This environment-centric view of wildfire risk is also evident at the policy level. In 2015, for example, <a href="https://www.gov.ca.gov/news.php?id=18906">a major funding package</a> in California for emergency firefighting costs was named the “drought package” as if drought alone was the cause of the problem.</p>
<p>These explanations were also on display after the 1991 Oakland/Berkeley Hills Fire which had – until this October – been the most destructive wildfire in California’s history. A Federal Emergency Management Agency <a href="http://www.hillsemergencyforum.org/docs/1991FEMAreport.pdf">report</a>, for example, blamed the blaze on “record high temperatures well into the 90s” as well as “hot dry winds [that] gusted and swirled through five years of drought-dry brush and groves of freeze damaged Monterey Pines and Eucalyptus groves.” </p>
<h2>Reckless development</h2>
<p>As these accounts suggest, threatening wildfires are frequently portrayed as a byproduct of warming weather, stubborn high-pressure zones and dry western landscapes. But what about the institutions, reckless policies and billions of dollars worth of financial incentives that help produce dense human settlements and immense social risks on these landscapes? </p>
<p>Typically absent from the discussion are the powerful social and economic forces that turn historically active fire regimes into a string of deadly and costly wildfire disasters.</p>
<p>Across the Western United States, areas at the wildland urban interface have seen a <a href="http://www.iawfonline.org/pdf/WUI_Fact_Sheet_08012013.pdf">300 percent population growth rate</a> in the past 50 years. As of 2012, 46 million homes were located in the WUI. Based on current trends, that number is expected to increase to <a href="http://www.fs.fed.us/openspace/fote/national_forests_on_the_edge.html">54 million by 2022</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191918/original/file-20171025-25497-pof80a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The devastation in the Coffee Park Neighborhood of Santa Rosa, California was made worse by urban development in high-risk areas.</span>
<span class="attribution"><span class="source">AP Photo/Marcio Jose Sanchez</span></span>
</figcaption>
</figure>
<p>The most alarming suburbanization statistic, however, concerns what hasn’t been developed. As of 2008, <a href="http://headwaterseconomics.org/wildfire/fire-costs-background/">only 14 percent of private land</a> in areas at the wildland urban interface of the Western United States had undergone land conversion. By 2013, this number increased to 16 percent and will continue rising without growth limitation policies in place.</p>
<p>And where new developments do occur, cities should do better to acknowledge their high exposure to fire. Large swaths of areas impacted by the Wine Country Fires, including the Coffey Park Neighborhood in Santa Rosa and the Rockridge Neighborhood in the Oakland/Berkeley Hills, were not originally zoned as “Very High Fire Risk”. As a result, building codes were lax and did not include fire safe provisions. Moreover, municipal infrastructure such as narrow roads, exposed power lines and inadequate water conveyance systems hindered emergency response activities. </p>
<p>This leads us to a second and more fundamental “perfect storm” problem. Such language suggests that an unlucky and unpreventable alignment of environmental conditions is always required to make the unthinkable happen. </p>
<p>This is flawed logic. The conditions leading to the Northern California Wine Country and Oakland/Berkeley Hills fire disasters were neither unlucky nor unpreventable.</p>
<p>And such large fire disasters, while undesirable, should never be viewed as unthinkable. The truth is, we knew these fires were possible and that there were <a href="http://journals.sagepub.com/doi/abs/10.1177/0308518X16669511">inherent dangers</a> when these communities were built. </p>
<p>How did we know? The historically active fire regime in California and across the American West stands as a stark and foreboding reminder of these perilous landscapes. </p>
<p><iframe id="0Xdqu" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/0Xdqu/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>And yet, despite fully comprehending these immense fire risks, cities have continued to plan and extend human settlements further into already fire-prone areas. And this is on the heels, and sometimes coinciding with, many decades of intentional fire suppression policies which enabled fuel build-up across the Western United States. </p>
<p>As I argue in <a href="https://www.ucpress.edu/book.php?isbn=9780520292796">“Flame and Fortune in the American West”</a>, we tend to ignore these seemingly obvious risks because suburban landscapes are decidedly lucrative landscapes. These are areas that generate high levels of profit and revenue for interested parties near and far. This includes landholders, property developers, members of the construction industry, and city and county property tax offices, to name but a few. </p>
<p>The recent fires in Northern California were not the result of a perfect storm of unlucky factors or unforeseen conditions. Quite the contrary we could see these fires and their disastrous outcomes coming decades in advance. It was only a matter of <a href="http://www.tandfonline.com/doi/pdf/10.1080/00045608.2014.941736">time</a>. </p>
<p>Rather than pointing to unruly ecological conditions when explaining costly wildfires, we need to recognize the role society’s ravenous appetite to develop historically high-risk areas plays. Only then can we start to reverse calamitous urban planning trends.</p><img src="https://counter.theconversation.com/content/86128/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory L Simon does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The media and policymakers often say a ‘perfect storm’ of environmental factors cause wildfires but that ignores the role of irresponsible urban planning and development in raising fire risks.Gregory L Simon, Associate Professor of Geography and Environmental Studies, University of Colorado DenverLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/859662017-10-24T00:15:07Z2017-10-24T00:15:07ZCalifornia needs to rethink urban fire risk after wine country tragedy<figure><img src="https://images.theconversation.com/files/191278/original/file-20171022-13995-1j9wu4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Picking up the pieces after fire devastated the city of Santa Rose, California. </span> <span class="attribution"><span class="source">AP Photo/Jae C. Hong</span></span></figcaption></figure><p>We recently witnessed the wind-driven Tubbs fire blast its way through densely urbanized neighborhoods in Northern California, causing dozens of fatalities and thousands of home losses. This tragic event easily ranks as the most catastrophic fire <a href="http://www.fire.ca.gov/communications/downloads/fact_sheets/Top20_Destruction.pdf">in modern California history</a>. Stories of how fast the fire spread and how little time people had to evacuate are stunning.</p>
<p>Despite how unusual the devastation appears, we need to recognize that these structure-to-structure “urban conflagrations” have happened in the past and will happen again. Yet these fires revealed that we have key gaps in our policy and planning related to assessing risk in fire-prone environments.</p>
<p>What is increasingly clear to fire researchers <a href="http://ucanr.edu/?facultyid=1595">like me</a> is that losses on the human side are often driven by where and how we build our communities. This means we must <a href="https://www.americanscientist.org/article/coexisting-with-wildfire">learn to coexist with fire</a>, if we are going to inhabit fire-prone landscapes, just as we adapt to other natural hazards. An essential step is to shift our perspective from a focus on hazard to one that more comprehensively includes human vulnerabilities.</p>
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<h2>Mapping risk</h2>
<p>California is leading the way in mapping the danger that wildfires pose to human communities and, in particular, linking building codes to fire severities that may be expected in given location. The state’s <a href="http://www.fire.ca.gov/fire_prevention/fire_prevention_wildland">Fire Hazard Severity Zone maps</a> are an essential step in recognizing fire as an inevitable process that must be accommodated, similar to how we plan for floods, landslides, earthquakes and hurricanes.</p>
<p>What is missing from these maps, however, is extreme weather patterns. The <a href="http://onlinelibrary.wiley.com/doi/10.1029/2009GL041735/full">Santa Ana winds</a> of Southern California are a notable example. Strong, hot and dry wind episodes are associated with nearly all of our largest and most destructive wildfires, including the <a href="http://napavalleyregister.com/calistogan/news/local/tubbs-fire-reminds-locals-of-hanley-fire-of/article_dce8464f-1557-5956-a508-04fffe8d7043.html">1964 Hanley fire in Northern California</a> that burned an almost identical footprint to the Tubbs fire, yet relatively little is currently known about how often they occur across a landscape. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191279/original/file-20171022-13963-rljy8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Updating maps on fire risk should inform urban development.</span>
<span class="attribution"><span class="source">Cal Fire</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>New methods are becoming available for mapping and modeling winds, and future versions of the Fire Hazard Severity Zone maps will therefore include such weather conditions. Similar maps are also needed for fire-prone areas outside California.</p>
<p>Despite technical advances, a key problem with most mapped approaches to fire danger is that the focus is almost exclusively on characterizing the hazard – flame lengths, rates of spread or fire intensities of an oncoming wildfire – and much less on the vulnerabilities of what is actually exposed. The “<a href="http://silvis.forest.wisc.edu/maps/wui">wildland-urban interface</a>,” where developed lands are exposed to natural, flammable areas, is thus often mapped and assumed to be where the exposure ends.</p>
<p>Clearly this is not always the case. Analogous to when a levee fails, after a wildfire manages to ignite homes along the wildland-urban interface, many homes farther inside the neighborhood can quickly become exposed.</p>
<p>Depending on the building codes in place during their construction, these newly exposed structures may or may not be very fire-resistant. Their vulnerability to ignition can also be especially high if they are spaced closely together and the winds are strong, because that is when fire spread transitions to a structure-to-structure domino effect.</p>
<p>Better fire risk mapping means we should be able refine our notion and approach to assessing vulnerability.</p>
<h2>Reducing human exposure</h2>
<p>There are numerous reports of how difficult and deadly it was <a href="http://www.mercurynews.com/2017/10/09/santa-rosa-fire-how-a-sudden-firestorm-obliterated-a-city/">to evacuate during the Tubbs fire</a>. Apparently many people had almost no warning at all. This highlights the importance of both evacuation planning and evacuation communication systems, as getting out in time is what Americans tend to rely on in wildfire situations.</p>
<p>Although evacuation preparedness is nearly always mentioned in <a href="http://www.firewise.org/usa-recognition-program/cwpps.aspx">Community Wildfire Protection Plans</a> and <a href="http://www.readyforwildfire.org/Go-Evacuation-Guide/">standard guidance for home owners</a>, the overriding message is typically to “leave early” whenever possible.</p>
<p>While absolutely correct, this advice minimizes the importance of pre-fire evacuation planning and the short time there may be to get out. It takes quite a bit of thought and effort to anticipate being in such a crisis situation!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191280/original/file-20171022-13955-d22mwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An urban fire that gave many people little time to leave points to the need for better planning on evacuation.</span>
<span class="attribution"><span class="source">AP Photo/Marcio Jose Sanchez</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>What should one take, and where might one actually go?</p>
<p>On short notice, how does one account for pets, children or the elderly?</p>
<p>Is there a place one should retreat to, if evacuation orders are received too late or not at all?</p>
<p>This last question may be the one that gets the least attention, and the many fatalities in the Tubbs fire suggest that it requires much deeper consideration. Firefighters are often given <a href="https://www.nifc.gov/wfstar/downloads/safety_essays/Alexander_VICFFR_keynote_address.pdf">specific training</a> about what to do with limited evacuation options. For homeowners, however, <a href="http://www.readyforwildfire.org/What-To-Do-If-Trapped/">guidance can be sparse</a>.</p>
<p>When it is too late and too dangerous to evacuate safely, fallback options must be considered and communicated ahead of time. In an urban conflagration situation, local details dictate whether “<a href="http://firesafemendocino.org/creating-a-safety-zone-for-use-in-a-wildfire-emergency/">safety zones</a>” actually exist as places to take refuge. Given the real potential for such disasters, many communities should consider identifying (or building) key “hardened” structures to act as local-scale refuges.</p>
<p>Reducing human exposure involves more attention to what people must do during a wildfire, or even the rare urban conflagration. Safe evacuation deserves as much emphasis as reduction of fuels, such as creating defensible space around homes or larger scale fuel breaks by thinning vegetation around communities. </p>
<h2>A safer built environment</h2>
<p>From the scale of individual home construction up to the location and arrangement of development on a landscape, our communities should be better able to survive the natural hazards that occur there. This requires both short- and long-term strategies for achieving a safer built environment.</p>
<p>As a starting point, we must acknowledge that we currently have tens of thousands – possibly even hundreds of thousands – of homes constructed according to building codes that leave these structures vulnerable to ignition. Amazingly, however, there are very few <a href="http://thinisin.org/index.php/structural-ignitability/replacing-wood-roofs">examples of grant programs</a> to mitigate such vulnerabilities through retrofit programs to, for instance, replace wood shake shingle roofs or to upgrade attic and crawlspace vents to block embers from entering homes.</p>
<p>In contrast, there are millions of dollars in public funds spent annually on community-scale fuel reduction projects. These are common activities pursued by <a href="http://www.cafiresafecouncil.org/">Fire Safe Councils</a> in California and similar organizations in other states.</p>
<p>The same level of support should be available for mitigation of fire-related structure vulnerabilities as there is for hazards.</p>
<p>Over the long term, land use planning is probably the most effective tool available for creating safer communities. We must be more deliberate about how we develop on fire-prone landscapes, taking advantage of emerging hazard-mapping techniques.</p>
<p>The goal here is not necessarily to build fewer homes, but to design and site developments that avoid the highest hazard regions and concentrate development in the lowest hazard areas. This logic applies, to varying degrees, to constraining development with respect to other natural hazards.</p>
<p>Despite an aversion by some to land use planning, this strategy is simply common sense. It will also save lives and massive amounts of public resources over the long term.</p>
<p>Where we do choose to develop and inhabit hazard-prone environments, it may be necessary to design communities with “<a href="https://www.buildinggreen.com/op-ed/passive-survivability">passive survivability</a>” in mind, or the ability to withstand the event and have water and power for a few days. This provides both the built environment and the people within some basic protection for a limited time. </p>
<p>Strategies exist to lower the risk of fire in the current housing stock and to more carefully design and site future development where wildfires are possible. With increasing <a href="https://theconversation.com/wildfires-in-west-have-gotten-bigger-more-frequent-and-longer-since-the-1980s-42993">extremes expected</a> as climate continues to change, <a href="https://theconversation.com/why-hurricanes-harvey-and-irma-wont-lead-to-action-on-climate-change-83770">officially recognizing this link</a> and creating a safer built environment will only become more urgent.</p><img src="https://counter.theconversation.com/content/85966/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Max Moritz has received funding from Federal (e.g., NSF, USFS) and California State (e.g., CEC, CalFire) sources.</span></em></p>A California fire expert explains why municipalities need to reassess urban fire risk and take steps to learn how to coexist with fire.Max Moritz, Cooperative Extension Specialist, Wildland Fire, University of California, BerkeleyLicensed as Creative Commons – attribution, no derivatives.