Fire, as a force of nature, has been in existence since the dawn of time. From the Big Bang to the Big Burn,1 fire has helped make the world what it is today. Once the human race was able to use the process of combustion to create creature comforts and control the environment, life improved for most people.

It also was quickly understood that fire is an unforgiving force. Building a better life and a better world includes treating fire with respect and, for the most part, the world has become a better place because the human race has mastered the use of fire.


But not always. Accidental or uncontrollable fire has been traumatic to both life and property and birthed the fire profession industry. As a profession, the practice of mastering fire has various aspects ranging from fire prevention through fire engineering to fire suppression. To keep this article within a specific scope, the focus is on only one type of fire: wildfire and its impact on an urbanized society.


In the past, forests had forest fires and cities had structural fires. Seldom did the two environments collide. The U.S. fire legacy contains numerous stories of urban conflagrations. Very few of these incidents were caused by wildland fires entering cities prior to the turn of the 20th century. For example, Boston, Philadelphia, Baltimore and Chicago all suffered urban conflagrations from the late 1700s to the 1800s. Yet, there is little mention of wildland fires during those eras. The two fire problems were isolated from one another.


The convergence began when two famous fires occurred at the same time in October 1871. One was called the "Great Chicago Fire" and the second was called the "Peshtigo Fire."2 Both resulted in major loss of life and property. However, one created a watershed of concern over the need for fire prevention in cities while the second went mostly unobserved by the media.

There have always been wildfires on the landscape. Many devastating ones have occurred since European colonization. However, they were considered part of nature, not a threat to cities and towns. A firestorm in 1910 changed all of that - the "Big Burn" of 1910 killed 86 individuals and destroyed town after town. The difference between that firestorm and previous ones was that it occurred in the midst of the nation struggling over what policies were best to protect its natural assets. The battle over policy was shaped by the opinions of President Theodore Roosevelt and his hand-picked forestry advisor Gifford Pinchot. Well before the fires actually occurred, President Roosevelt made a speech that clearly stated his attitude:


"And now, first and foremost, you can never afford to forget for one moment what the objective of our forest policy is. The object is not to preserve the forests because they are beautiful, though that is good in itself, nor because they are refuges of the wild creatures of the wilderness, though that, too is good in itself, but the one primary object of our forest policy, as of the land policy of the United States, is the making of prosperous homes, every other consideration comes as secondary. Your attention must be directed to the preservation of the forests, not as an end in itself, but as a means of preserving and increasing the prosperity of the nation".3

Behind this contention was the idea that forests were being devastated by lumbering and special interests and that preservation really meant restraint on the use of forest products.


The year 2010 represents the 100th anniversary of the official creation of U.S. national policy on dealing with wildland fires. These policies were shaped by the points of view of three key people: President Roosevelt, Gifford Pinchot and H.M. Suter.


Pinchot, both friend and appointee of President Roosevelt, had been appointed the first Chief of the U.S. Forest Service in 1905. At the time the Big Burn occurred in 1910, he was on a crusade to preserve the national forests. There were many people - influential corporate barons and their politicians who were just as dedicated and opposed to Pinchot's policies. Out of the Big Burn and its political firestorm emerged a common enemy: wildfire. A forester named H.M. Suter wrote an article that reduced the argument about preserving the forests to one sentence.4 According to Suter, the first objective in forest protection was "to extinguish small fires promptly and thus avoid the great expenditures inherent in well-nigh hopeless struggles with conflagrations." The policy of exclusion of fire from the natural way of things was born.

For the next 30 years, the political debate about protecting one of America's valuable forest resources was waged at every possible level of involvement. The issue was not solely focused on the consequences of fire's exclusion from the natural world, but also on contentions that preservation of timberland was in the national interest.


At the center of the fight was the U.S. Forest Service (USFS), which fought for and received the responsibility for wildfire protection on federal lands. This was a fundamental decision as it completely shaped the intervening 100 years of wildland firefighting history.


Because USFS was designated the premier agency of U.S. wildfire protection, wildfires and their consequences have been largely managed by forest or land agencies around the country. When wildfires burned homes, it was considered to be collateral damage and secondary to protecting the forests.


The past contains evidence that the problem of forest fires did not remain in the wildlands, but rather came down into the urbanized part of the country. As early as 1928, less than two decades after the 1910 fire, the cities of Oakland and Berkeley were struck by a fire that could best be classified as the classic wildland urban interface fire.5 The fire started as a wildfire and came into the city where it converted to an urban conflagration. The period since 1930, therefore, could best be described as the beginning of the wildland-urban interface problem. It existed where the forests per se were not the problem, but the homes in or near them were.


In the aftermath of the 1993 Fire Storm, the California State Fire Marshal's Office received a grant from the U.S. Fire Administration to write an urban-wildland interface code. Following are the foundational premises of the present "wildfire" problem:

  • Wildfires are widely perceived as a single type of fire much like structure fire is used to separate building fires from vehicle, subterranean or vegetation-fuel fires. However, this simple designation doesn't begin to define the more complex variations of wildfires and their benefit/loss consequences.
  • Wildfires can be divided into two categories: the vegetation-is-the-primary-fuel "wildland fire," and the building-is-the-primary-fuel "interface fire." The term "wildland fire" is a poor choice for this category, but it is most commonly recognized as a name for a large fire that is burning in a wildland setting far enough away from human communities that it is not a direct threat. In contrast, an "interface fire" is a fire that burns in and around human communities where buildings contribute to the fire load. Each of these fire types has a very different set of behaviors, fire physics, mitigation and management solutions, and consequences.
  • Too many homes are burning in concentrated times and places. This is driving a perception that the wildfire issue is a large fire problem, and this is true when viewed from a geographic (California) or temporal (single day) perspective. When viewed from an actuarial perspective, however, interface fire losses are not a primary loss-leader for the insurance industry, nor do they represent a significant volume of structural losses in America. More lives and homes are lost to standard residential fires every year than to wildfires.
  • Fires of both types - wildland and interface - are growing in frequency, severity and cost. Frequency is a function of increased human activity and its ignition source impact; severity is a function of vegetation fuel loads and defensively oriented fire-suppression policies; and cost is a function of the rising personnel and equipment costs for firefighting, increased deployment of those resources before, during and after the fire threat event, and improved accounting for both direct and indirect losses to human and natural environments.
  • There are two significant consequence categories of the wildfire problem: human and natural. Assuming for a moment that one can separate the two, the human consequence falls mainly on the damage to lives, homes, communities and economies. The other consequence is environmental in both the short and long-term. Short-term environmental impacts from fire are the obvious destruction of plant and animal life, habitat, air quality and watershed functions such as erosion, water quality and negative impact on aquatic life. The longer-term impacts of the wildfire event focus more on the change of habitat, plant and animal diversity, carbon release losses, watershed degradation and soil damage.

The immediate goal is to recognize that there are two separate problems. The first is that forest/ecosystem health, watershed degradation, fuels buildup, air quality and loss of land development potential are real environmental issues. The second is that public and firefighter safety is a risk mitigation problem of significant importance. One hundred years after the Big Burn, the United States is still struggling with a "growing fire problem" in the eyes of the nation's forest and fire agencies.


Currently in California and other parts of the country, there are major efforts underway that acknowledge two core facts of the wildfire threat. First is that fighting wildfires (interface or wildland-type) has been lifted out of military organizational philosophy. Fires are fought much like going to war - same terms, intent, mission and technologies. Second, the present approach has not succeeded; otherwise, losses would be declining rather than increasing. To succeed, it is necessary to use the tools of prevention, engineering and mitigation rigorously before the fire event occurs. California is steadily developing or implementing these five approaches for WUI fires: firesafe land use planning, building construction and design, vegetative fuels management, community education, and first responder training.


Currently the California land use approach employs several tools relevant to both interface and wildland fires. The state has some of the most rigorous planning requirements in the nation and requires wildfire planning as part of city, county and state planning documents. From state level hazard planning to local residential subdivision development plans, the public safety and environmental impact of fire, fire suppression and fuels management are beginning to be systematically addressed. Many areas prepare community wildfire protection plans and specific fire protection plans that incorporate fire behavior modeling. Mitigation prescriptions customized for the building project are becoming more common for larger subdivision projects.


Building materials, design and placement are the linchpin key for mitigation of interface fire consequences. The engineering world is just coming to force on this issue and the role of the engineer and researcher is critical to success. The national model codes for both NFPA and ICC have relevant sections that deal with wildfire-specific building concerns. An important shift is that for interface fires, one must prevent the building from igniting rather than simply slowing its rate of burn. When many homes are burning simultaneously, there are too few fire engines to go around and suppress all the fires; the consequence is that homes burn to the ground. The concept and technology of "ignition-resistant"6 recognizes that it is necessary to reduce the buildings' vulnerability to the small wind-carried embers that swirl around an interface fire and assault the home with a blizzard of ignition sources.


California Building and Fire Codes (CBC/CFC) have specific chapters for residential and commercial construction in the WUI. These provisions are the result of the limited research, laboratory testing and technical committee development available and are continually evolving. More research is needed to fully understand the mechanism of exposure in an interface fire event, how building materials and applications reduce that exposure, and how to develop "barrier" technologies that keep all three main types of heat sources from igniting buildings. Across the country, there are a few bright spots to watch as the research world starts to harness focus. A few examples are: California State University Cal Poly - San Luis Obispo, which is developing a fire protection engineering graduate program and looking toward the applied building sciences for interface fires; National Institute of Standards and Technology (NIST), which is pursuing modeling and testing specific to the interface fire building exposure mechanisms; and the insurance-industry sponsored Institute for Building and Home Safety (IBHS), which is constructing a center for natural hazard building materials testing that will identify more about wildfire exposures and appropriate building materials and technologies.


Meanwhile, California building codes are focused on keeping the home from igniting and code provisions cover roof types (Classes A/B/C), eave and vent design and screening for embers, wall coverings, dual-pane windows with tempered glass, and deck materials. Like other state-adopted provisions, these are statewide minimums for construction; local agencies must use these standards or adopt more stringent ones; also, all homes built in California in a designated Fire Hazard Severity Zone must be built to these code standards. Mobile or manufactured homes for sale in the state also are included in these requirements through the state authorities that regulate that industry.


It is important to break down interface fire fuels into two types: structural and vegetative. Building standards address the home-as-fuel-type issue by improving ignition resistance, exposure and building materials. Vegetative fuels are most effectively addressed through a linear perspective-the closer the fuel is to the home, the more impact it has on structural survivability. This approach recognizes that the type of wildfire primarily being addressed is the interface fire and its impact on life and property. Based on past experience, most homes ignite and burn as a result of exposure to embers or undereave bushes (conductive heat) or to adjacent house fires (radiative heat), so the vegetative fuels treatment priority order is best begun at the house, then extends to the yard, the yard next door, the community vegetation, and finally, the regional vegetation.


As in structural fire prevention, all of a building's built-in fire safety features can be wasted effort if the occupants have no idea how to respond to an alarm, to exit effectively or maintain their safety systems. This also applies to interface fire protection-communities must be educated and trained on how and why their home defense features must be maintained, how their emergency alerting system works, how to evacuate and return, and what to realistically expect from the fire service in large-scale WUI events.


Finally, the education of public safety first responders is crucial. Fire departments traditionally focus on the skills necessary to maintain scene safety and fire suppression needs, but interface fires require a broader skill set. Massive and rapid evacuations in a dynamic environment, the confluence of multiple agencies, demand for incident intelligence and information all reach beyond the currently required training for wildfire suppression tactics. This includes multi-jurisdictional training on the National Incident Management System/Incident Command System, large-scale evacuation drills, emergency operations centers and incident command post relationships, and communications and information/intelligence-sharing strategies.


In order to envision the future, it is necessary to have a strong grasp of the present. One term that is used for this is "situational awareness."


Situational awareness is the primary basis for subsequent decision making and performance in the operation of complex, dynamic systems. Developing a situational awareness of the international wildfire issue is a daunting task because so many factors are threaded into the whole. The Big Burn of 1910 birthed a simple approach to fire management - suppress all wildfires. Observations one hundred years later are that the problem is increasingly complex and the traditional solutions are losing effectiveness. A broader perspective is emerging - one that begins to redefine the discipline of "wildfire." These observations include:

  • WUI fire problem-solving is growing out of federal land management agencies and is migrating toward local government and private sectors.
  • A growing body of technical experts are beginning to agree on a few fundamental starting points such as terminology, problem description, trend analysis and research requirements.
  • Wildfire mitigations such as defensible space, building engineering and land use planning are described as the necessary missing links by all WUI experts but only some policy makers, firefighters and citizens.
  • The environmental community is beginning to focus opposition to development and fire suppression as negative consequences to ecosystems.
  • Large "landscape level" fuels management is being challenged as a solution to interface fire losses.
  • Climate change and increased wildfire threat are emerging as having possible environmental consequences.
  • There is collective, concentrated focus on the WUI issue from the fire service, insurance industry, policymakers, research institutions and universities, and partnered disciplines such as engineering, building and planning fields.
  • The "WUI Problem" is creating an independent, capitalistic industry. This refers to the range of private interests that are now participating in the problem-solving process by creatively inventing products and services such as firefighters-for-hire, home safety systems, individual or community notification technologies, building products or specialized WUI consulting services for landscaping, architecture and land use planning. These are the harbingers of a large-scale paradigm shift.
  • Technology, specifically GIS and remote sensing, offers solutions that take advantage of every aspect of the problem, from risk analysis to firefighting to community education.

Some of the current challenges of the WUI fire problem to which the engineering world can contribute solutions include:

  • Developing a systematic taxonomy of interface fires. It is not possible to develop solid science without a common vocabulary that describes types of fires, behaviors, impacts and losses. An example is the Hurricane Scale: a Category 4 hurricane is measured the same around the world.
  • Defining the causes of structural ignition and how interface fire behavior is impacting buildings. A common methodology is needed to describe post-fire impact, data gathering components and data-sharing such as has evolved for evaluating structural fire for interior components. Testing standards, building materials, lab research - all need to be supplied with consistently common data in order to advance research and design.
  • Acknowledging that interface fires are not natural disasters anymore than urban conflagrations were. They are predictable fire events that require people and buildings. Today's interface fires have a lot in common with the loss of entire wood-roofed cities a few hundred years ago. Building design, placement, landscaping, water and roads, passive and active fire protection, and appropriately scaled fire departments have helped eliminate urban conflagrations - the same will hold true for interface fires.

All the above must be able to take research and technology development and turn it into actions at a granular (house by house - neighborhood by neighborhood - city by city) level. Converting fire loss research into cost-effective solutions that can be integrated into the existing risk management process is crucial.


There is a classic definition of insanity that goes "doing the same thing over and over again and expecting a different result." The interface fire future must include doing something different by developing, testing, and discarding or accepting solutions in a systematic fashion to shape the wildfire battlefield of the future.


Ronny J. Coleman and Kate Dargan are retired California State Fire Marshals.



  1. Egan, Timothy, The Big Burn; Teddy Roosevelt and the Fire that saved America, Harcourt Mifflin, 2009.
  2. Bales, R. The Great Chicago Fire and the Myth of Mrs. O'Leary's Cow, McFarland & Co.: Jefferson, NC, 2002.
  3. Speech given to Society of American Foresters in Washington, DC, March 26, 1903.
  4. Biltmore Estate, Forestry Department Managers Records, Series S, May 16, 1904.
  5. Berkeley Conflagration 1923, Virtual Museum of the City of San Francisco,
  6. Urban-Wildland Interface Code, International Code Council, Washington, DC, 2009.