Defensible Space Must be Properly Placed

By: Todd McNeal

Defensible space; simply defined as the area around a structure where fuels have been modified to increase the likelihood the structure will survive a wildland fire front, has evolved through many definition iterations since its introduction. This concept evolution is based on continual research by members of the fire science community and personal experience of all-risk firefighters charged with the suppression of fires in the wildland urban interface (WUI).

Adding to this evolution, and drive for constant revision, are the numerous resource conservation groups, Fire Safe and Fire Wise councils that assist property owners by providing information and education to better prepare their homes for the inevitable wildland fire season. When property owners modify the surrounding and adjoining vegetation, they assist fire personnel with their decisions during the structure triage phase of operations in the WUI.

The presentation of defensible space around a structure comes in many forms and differs as fuels and building construction features change. If a person was to travel the multitude of communities in the fire prone areas of our nation, they would witness the broad spectrum of personal property preparation from excessive clearance and fire resistive construction, to non-existent defensible space, problematic construction materials, and poor topographic placement. While understanding what is defensible space and being ever vigilant in assessment of its quality during triage decisions is critical, unfortunately placement of that defensible space in the greater landscape is often overlooked. This lapse in complete defensible space evaluation is unfortunate but understandable due to the often chaotic nature of initial attack on rapidly growing fires or the contrary, fire located at a distance and personnel caught off guard when conditions change. Add the familiar fact of a massive mobilization of resources from out of the area, unfamiliar with local factors, to certain problematic interface communities during large fires, and clearly the stage is set for personnel to miss the defensible space “big picture”. Failure to evaluate this “big picture” of a structure’s defensible space placement in the landscape, while making structure triage decisions about that structure, can be a dangerous error. No matter how modified the fuels, or in some cases the complete absence of them, a safe place to stay and protect will not be created if the landscape concentrates, channels, or delivers the approaching fire’s intensity directly upon the structure’s location. Because of this fact I strongly encourage all fire suppression resources tasked with structure protection to remember the statement:

Defensible space must be properly placed.

In this day and age the amount of information available to individual homeowners on the topic of defensible space is astounding, from traditional sources like publications and brochures, to the trade shows and conferences, and the seemingly endless amount of information available via the internet. Direct access to information benefits all in our communities, and if adhered to, may increase firefighter safety in the traditionally dangerous arena of the wildland urban interface. As a firefighter asked to serve our community when threatened by wildfire and appreciative of information available to property owners regarding defensible space, I must interject my observations and concerns of the near miss and unfortunately fatal fires in recent large WUI incidents. In particular, I would like to draw attention to the incidents that reinforce my observations, research and subsequent suggestions for future firefighting operations; the Cedar, the Esperanza, and the Jesusita Fires.

Let me first make the humble and sincere statement that I am in no way trying to point blame, deficiency, lack of skills, deficient training, limited experience, poor situational awareness or even inferior equipment, with regards to the agencies and personnel involved in the listed tragedies or accidents. I am merely citing these incidents as examples of how even with defensible space created around structures, terrain and local factors can channel fire upon a specific location with disastrous results. I was not present at any of the mentioned incidents, and am in no way trying to second guess the decisions made by those present and involved. Honestly and truthfully, I am deeply appreciative of the sacrifice made by all involved, especially the Firefighters, who in some cases served their community to the fullest extent possible, and gave their lives, protecting the core of all Firefighter’s mission, the protection of life, property and environment. For the greater good and betterment of the Fire Service, we as members of the Fire service must make it our obligation, duty, and show of respect, to use these incidents as means to better prepare ourselves for the rigors of the job. Because of the expectations of our communities, and the commitment each one of us in the service have made to our friends and family, to perform our duties in the safest and smartest possible way, to ensure our return at end of each shift or assignment, we must learn from the sacrifice of others. By reflecting, researching and training to improve our safety, we respect and pay tribute to those members of our service who have given all; we must train and learn in their honor.

To assist the Fire Service in that promise and important mission, I would like to offer the outwardly appearing simple statement as read in the title of this article; “defensible space must be properly placed”. As all reading can attest this appears to be another statement of the obvious that we often encounter while training, or reflecting on the basic safety concepts of operations in the WUI. However, I challenge all to explore the subtle implications of this statement. Upon further reflection, it becomes obvious there are numerous issues imbedded within this statement, all of which have serious firefighter safety implications. The many principals of accurate situational awareness, the dynamic nature of the interrelated relationships of fuels, weather and topography, the constant revision of tactical and strategic priorities, all required to be constantly processed during the high pressure atmosphere of WUI operations; is almost overwhelming. The amount of interconnected wildland fire suppression training concepts contained within the statement mandates thorough analysis. It is this basic statement, applied to future operations in the WUI, that I hope all Firefighters digest and use as a piece of their risk benefit analysis, structural triage, and daily suppression responses. If as an individual you take the time to understand and process the entire situation presented to you, then you have completed the first vital steps in answering the most important question; where can I safely engage the fire given the environmental variables on today’s shift?

All of the incidents I have listed provide firefighters with proof that if the entire concept of defensible space is not fully evaluated, especially the placement of the residence in the topography or how susceptible the structure is to the influence of topographical fire behavior impacts , personnel are exposing themselves to excessive risk. For members of the fire service the definition of defensible space needs to have more scrutiny applied than merely noting the horizontal distance of vegetation from your house. Although we train to the fact that there is a three dimensional aspect to the fire environment, often times this concept is not in the forefront of firefighter’s minds during suppression operations. The fire is moving quickly, other homes are burning and suppression resources are stretched thin, all distracting the personnel operating in the WUI to more immediate concerns. Therefore, by identifying the significant priority of analysis of your present location in the landscape, before we are tactically engaged and committed, we increase our safety.

This analysis starts within your initial attack area, and should grow from that point to include all of the areas you may have the potential to respond, from assisting the adjoining agency, to supporting statewide mutual aid. Although it is impossible to have specific knowledge of the entire State in which you live, you can develop a systematic approach to decision making that can be applied anywhere, under any incident specific variables. Start this process by gathering as much information about the local factors influencing fuels, weather and topography. This information is readily available from a variety of sources including; the internet, local residents, local jurisdiction emergency personnel, topographic maps and satellite imagery just to list a few. With the prevalence of computers in our apparatus and the growing numbers of “smart” phones with access to the internet, the information is literally at your finger tips.

Never before in the history of wildland firefighting has the availability of site specific information been accessible to personnel, as in the present times. Within minutes, you can look up the fire most likely to be ordering resources, find Incident Action Plans and maps, obtain weather and fire behavior forecasts, and even remotely observe local roads and building construction via street view pictures posted on popular mapping sites. Add to that the free applications that allow one to rotate the landscape to see terrain in three dimensions, the amount of information that can be used for situational awareness and increased safety is truly amazing. However, if you do not have access to any of the information available remotely, you can still apply the basic skills of observation while travelling across the landscape to help in identifying locations that will pose safety concerns due to topographical influences. Although the electronic information is valuable, technology can fail, batteries can run out, the internet can collapse, or you are operating without a signal, there is no replacement for the basic skill of map reading and understanding how fire moves across the landscape. Recognize features and elements that produce problematic and dangerous fire behavior, like chimneys and continuous fuels. Use the skills of observation to interpret the situation, look past the area directly surrounding the structure you are assigned and determine what influences in the larger area are at work to potentially deliver dangerous fire behavior to your area of deceptively adequate defensible space. Much like one of the common denominators of tragedy fires; fires burning in deceptively light fuels, so can the presence of defensible space lure a person into a false sense of security, and the failure to identify the placement of the assignment on the topography, both with potentially tragic outcomes. Please take a moment to look at the picture below, pulled from the Esperanza Accident Report, to see the possible influence of topographic channeling, and focusing of fire behavior energy at the accident site.

This picture simply and graphically illustrates the concepts I am trying to convey. The sobering clarity provided by this perspective, after the accident has occurred, should serve as a reminder to all personnel assigned to structure protection in the future, the potency of topographic influences on fire behavior. Note the topography below the site, and how wind in alignment with the drainage, combined with the focusing of the fire’s convective heat and ember shower by the drainage; the amount of defensible space around the home couldn’t possibly provide safety to the personnel given the incident variables of that day.

As people tasked with the mobilization and protection of homes during WUI fire, it is incumbent upon us to be as well trained and prepared as possible. This preparation begins with refining the skills of rapid assessment of site specific variables to determine a safe location to operate and tactical priorities. During the particularly challenging and significant social and political implications of fires burning in the WUI, Firefighters may focus in on the mission at hand; thereby unknowingly reduce their ability to fully evaluate their location on the terrain. Regardless of the amount of fuels reduction, the construction features of a particular house, even the directly improved defensible space provided by the owner’s preparation, if the greater topographic influence results in fire behavior being drawn to your location, the outcome is dangerous and inevitable. During the upcoming wildland fire season, and when assigned to structure protection, please remember to always ask if the defensible space is properly placed.