Reducing the Wildland Fire Threat to Homes: Where and How Much? 1

Understanding how ignitions occur is critical for effectively mitigating home fire losses during wildland fires. The threat of life and property losses during wildland fires is a significant issue for Federal, State, and local agencies that have responsibilities involving homes within and adjacent to wildlands. Agencies have shifted attention to communities adjacent to wildlands through pre-suppression and suppression activities. Research for the Structure Ignition Assessment Model (SIAM) that includes modeling, experiments, and case studies indicates that effective residential fire loss mitigation must focus on the home and its immediate surroundings. This has significant implications far agency policy and specific activities such as hazard mapping and fuel management. The threat of life and property losses during wildland fires is a significant issue for Federal, State, and local fire and planning agencies who must consider residential development within and adjacent to wildlands. The 1995 USDA Forest Service Strategic Assessment of Fire Management (USDA Forest Service 1995) lists five principal fire management issues. One of those issues is the “loss of lives, property, and resources associated with fire in the wildland/urban interface” (p. 3). The report further identifies “the management of fire and fuels in the wildland/urban interface” as a topic for further assessment. Because this is more than a Forest Service issue, the National Wildland/Urban Interface Fire Protection Program, a multi-agency endeavor, has been established for over a decade and is sponsored by the Department of Interior land management agencies, the USDA Forest Service, the National Association of State Foresters, and the National Fire Protection Association. This program also has an advisory committee associated with the multi-agency National Wildfire Coordinating Group. These examples indicate that the wildland fire threat to homes significantly influences fire management policies and suggests that this issue has significant economic impacts through management activities, direct property losses, and associated tort claims. The wildland fire threat to homes is commonly termed the wildland-urban interface (W-UI) fire problem. This and similar terms (e.g., wildland-urban intermix) refer to an area or location where a wildland fire can potentially ignite Homes. A senior physicist at the Stanford Research Institute, C.P. Butler (1974), coined the term “urban-wildland interface” and described this fire problem: In its simplest terms, the fire interface is any point where the fuel feeding a wildfire changes from natural (wildland) fuel to man-made (urban) fuel. …For this to happen, wildland fire must be close enough for its flying brands or flames to contact the flammable parts of the structure (p. 3). In his definition, Butler provides important references to the characteristics of this problem. He identifies homes (“urban”) as potential fuel and indicates that the distance between the wildland fire and the home (“close enough”) is an important factor for structure ignition. How close the fire is to a home relates to how much heat the structure will receive.