A REPORTER FROM A LOCAL public radio station recently called me to ask about national wildfire trends and the wildland/urban interface, also referred to as the WUI. Although her questions were straightforward, they reminded me how easy it is to take the public’s understanding of the WUI for granted. As the media will no doubt refer to the WUI again soon as the wildfire season ramps up, I thought it was a good opportunity to revisit some key points.
First, the basics: What do we really mean by the term wildland/urban interface? With multiple definitions out there, it can be confusing. At NFPA, we explain the WUI not as a pre-established location but as a set of conditions that can exist in nearly every community. The WUI is determined by the combustibility of structures and their proximity to vegetation and other structures, the type and distribution of vegetation, climate and weather patterns, fire history, topography and other landscape features, access, and more.
It’s worth noting that, in addition to the estimated 50 million housing units located in the WUI nationwide, there are typically many other important community assets located in wildfire-prone areas, including utilities, highways, bridges, watersheds, forests, natural areas, and parks.
Because WUI conditions can vary abruptly, even in the same community, there is often more than one “look” to a community’s WUI. It’s easy to underestimate the wildfire threat if we don’t realize the prevalence of WUI conditions or if we limit our WUI mental picture only to areas that have wooden cabins scattered in a remote wilderness area. In reality, many development patterns, many of which exist in close proximity to one another, can be classified as the WUI.
Colorado Springs, Colorado, is a great example. During various stages of last year’s Waldo Canyon Fire, three different neighborhoods in the city’s boundaries were threatened, from very dense suburban development to areas with private homes on large vegetated lots. Though these neighborhoods shared a few features, they also had their own unique topographies, housing densities, access routes, landscapes, and other built or environmental conditions.
WUIs can also vary broadly across the country. Heavier population densities in the eastern and southeastern United States mean that a smaller WUI fire can have a significant impact. In March, a wildfire in Pigeon Forge, Tennessee, burned only about 200 acres (81 hectares), but it destroyed more than 50 homes due to their closely clustered development pattern. Western wildfires are often measured in the thousands of acres, but structure losses can vary—fire size does not always correlate with structure loss.
Understanding WUI conditions, including an area’s fire risk, helps us ask the right questions: What kind of wildland/urban interface do I live in? What do I need to think about to prepare my home, my neighborhood, or my community for wildfire? What other assets are at risk? This understanding also helps us set priorities for our risk reduction activities, including public outreach programs such as Fire Adapted Communities
and Firewise® Communities
For more information on the WUI, check out the new publication from the USDA Forest Service, Wildfire, Wildlands, and People: Understanding and Preparing for Wildfire in the Wildland/Urban Interface, at fs.fed.us/rm/publications
Molly Mowery is program manager for Fire Adapted Communities and International Outreach.