Last year’s wildfire season was one of the worst on record, and whether or not this year's tops it (a likely outcome), it’s already off to a horrifically tragic start: 19 elite firefighters perished in a blaze outside Prescott, Ariz., on Sunday -- the most to die fighting a single wildfire in 80 years. Even before the deadly Yarnell Hill blaze began, the usual suspects were asking: What does climate change have to do with wildfires? James West of Climate Desk addressed this maddening question a couple of weeks ago and The New York Times addresses it today (and David Roberts addressed it last year).
But there’s another human-caused problem making wildfires worse: the exurbs. Or, to use the technical term, the “wildland-urban interface” or WUI, where development meets and mingles with fire-prone wildlands. The New York Times describes such areas, which include Yarnell, Ariz.:
Those expanding communities, with rural views but more urban economies, have been the focus of concern among federal and state officials for a decade or more. While such regions are more plentiful in the East, it is in the areas west of the 100th longitude, reaching from West Texas and the Dakotas to the Pacific Ocean, where the natural aridity, increasingly exacerbated by climate change, makes fires a common threat.
In the West in the 1990s, more than 2.2 million housing units were added in these fire-prone areas, according to testimony by Roger B. Hammer [PDF], a demographer at Oregon State University and a leading authority on the issue. Speaking to a House subcommittee in 2008, he called this a “wicked problem,” and predicted an additional 12.3 million homes would be built in such areas in Western states — more than double the current numbers.
According to a U.S. Forest Service Study [PDF], one-third of all U.S. housing units now sit in the WUI, and the total area classified as WUI increased by 18 percent between 1990 and 2000. These neighborhoods, bucolic in theory with their combination of suburban amenities and easy access to wilderness, have become ubiquitous in the West, the study reports:
In the Rocky Mountains and the Southwest, virtually every urban area has a large ring of WUI, as a result of persistent population growth in the region that has generated medium and low-density housing in low-elevation forested areas.