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Structure Ignition in the Wildland/ Urban Interface by Jennifer Klugh, Fire Education & Information Specialist Anchorage Fire Department July 2007 If you live in the Wildland/ Urban Interface (WUI), it is very likely that you are aware of the potential for a wildland fire to occur in these areas of the Municipality of Anchorage.  The WUI is defined by NFPA 299, Standard for Protection of Life and Property from Wildfire, as "an area where development and wildland fuels meet at a well-defined boundary."  This area comprises much of the Anchorage Hillside, Chugiak-Eagle River and Turnagain Arm communities. However, this boundary is not well-defined in the MOA because there are multiple residences within forested areas. Another term, wildland/urban intermix, differentiates a more specific type of area.  NFPA 299 defines this intermix as "an area where development and wildland fuels meet with no clearly defined boundary." 1.  Wildland-urban interface 2.  Wildland-urban intermix What does this mean for those of us who reside in the WUI?  Be PROACTIVE, not REACTIVE. Preparation for wildland fire is everyone's responsibility; YOU have the greatest impact on the actions that take place on your private property.  Federal, state and local land management agencies can mitigate the hazards on the land they   manage, but private homeowners must initiate changes on their own property.  Often times, focus during a wildfire is placed on the actual flame front of a wildland fire as the area of greatest concern.  This can evoke not only fear but a feeling of helplessness in anyone facing a nearby fire.  Dr. Jack Cohen, a research scientist with the USDA Forest Service at the Missoula Fire Sciences Lab, has conducted extensive research that indicates "the flames of high intensity wildland fires do not directly ignite homes at separation distances beyond 100 feet."  Cohen's research has shown a home's characteristics, exterior materials and design, in relation to the immediate area around a home within 100 feet principally determine the home ignition potential. The home and its immediate surroundings are referred to as the home ignition zone. In reality it is the embers, or "firebrands," traveling with the winds that pose the greatest risk for multiple home ignitions within that zone.  This is due to a combination of factors, namely numerous embers created during a wildland fire and the distance they travel.  Embers can smolder for several hours before an ignition occurs, often in an evacuated neighborhood where fire fighting resources will be stretched and could very easily overlook spot fires created by smoldering embers. Dr. Jack Cohen identified four of the most important areas of the home itself that need attention to prevent ignition from wildland fire. 1.  Wood roofing:  The most influential area of the home when examining ignition potential.  Studies have shown that a house with a non-combustible roof is about 90% more likely to survive the effects of a fire.  During the Bel-Air fire of 1961, 95% of the homes with non-flammable roofs and a 30- to 50-foot buffer from the burning thicket survived. In 1990, 86% of the homes with non-flammable roofs and 30-foot buffers survived the Painted Cave fire in Santa Barbara, California.  Non-combustible alternatives to wood are metal, asphalt shingles and composite shingles designed to resemble wood shakes. 2.  Attic and eave vents:  These are areas on your structure that when left open to the entrance of firebrands, can easily accommodate the entrance of embers into your home.  These areas should be covered with 1/8" non-combustible screening.  3.  Rain gutters and rooftops: These are areas vulnerable to embers and could result in ignition of the materials that have accumulated such as needles, leaves and moss.  To mitigate this risk, rain gutters and rooftops should be cleared of combustible debris at least twice per season. 4.  Combustibles near the home:  This item seems like an obvious area of concern, but it is often overlooked.  Conifer trees, firewood, gasoline, leaves, even lawn furniture can lead to a home ignition if embers collect on these combustibles.  Studies have shown that even wooden decks fare well in fires when they have been cleared of combustibles.  Additionally, metal flashing can be installed where decks or wood fences and exterior walls of homes meet.  The Anchorage Fire Department recommends removing all conifer trees within 15 feet of the home, and additional thinning and pruning extending beyond this area.  The basic rule is, "Does it burn," and "Is it connected to my house?"   The Caribou Hills Fire on the Kenai Peninsula in 2007 illustrates how wild reed grasses can be a major factor in fire spread.  Initial assessments of the burned areas of this fire show it was carried through the dry, matted down grass that had collected over the years.  In areas where the grass had been removed or maintained, the fire ceased to spread.  There was also beetle-killed and live spruce trees both standing and on the ground, which added to the intensity of the fire but did not provide the fast moving potential for spread in the same way as the dry grass.  This local observation illustrates the importance of property maintenance performed by homeowners in the prevention of home ignition from wildland fire. Remember, preparation for wildland fire is everyone's responsibility.   Wildfires Happen, Be Ready!

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