As Wildfires Grow, Millions of Homes Are Being Built in Harm’s Way
By Nadja Popovich and Brad Plumer, Sept. 9, 2022, NY Times
Across the Western United States, wildfires are growing larger and more severe as global warming intensifies. At the same time, new data shows, more Americans than ever are moving to parts of the country more likely to burn, raising the odds of
catastrophe.
In 2020, more than 16 million homes in the West were located in fire-prone areas near forests, grasslands and shrub lands, where the risks of conflagration are highest. That’s a rise from roughly 10 million homes in 1990, according to research
published Friday from the University of Wisconsin-Madison and the United States Forest Service.
“That’s the perfect storm,” said Volker Radeloff, a professor of forest ecology at the University of Wisconsin-Madison, who helped lead the research. “Millions of houses have been built in places that will sooner or later burn,” he said, even
as climate change increases the risks of major wildfires across the West with extreme heat and dryness.
Nowhere is this dynamic more visible than in California, where eight of the largest blazes on record have struck in the past five years. The state now has roughly 5.1 million homes in what’s known as the “wildland-urban interface,” the term for
areas, often on the outskirts of cities, where houses and other development are built near or among flammable wild vegetation.
The foothills of the Sierra Nevada have seen especially fast growth.
When wildfires erupt, they tend to inflict most of their damage in these transitional zones where homes and businesses encroach on otherwise undeveloped wilderness.
Examples include the Camp Fire in 2018 that incinerated the forest-surrounded town of Paradise, Calif., or the Woolsey Fire that same year, which tore through shrub- and grass-covered canyons northwest of Los Angeles and burned more than 1,600 structures.
There’s no single reason for the explosion of development in the wildland-urban interface, or WUI (pronounced “woo-ee”). Some people move to live closer to nature, or because costs are lower. In California, many cities have restricted development
in denser downtown areas, exacerbating the state’s housing crisis and pushing people to the outer fringes.
“By and large, most new development housing construction in California has been going on in the periphery of existing urban areas,” said Karen Chapple, a professor of city and regional planning at the University of California, Berkeley, and co-author
of a report on rebuilding after wildfire disasters. “It’s happening because that’s where the land is cheap. So we end up putting housing in these very vulnerable areas.”
Similar trends can be seen throughout the West. In Colorado, the number of homes built in the wildland-urban interface has nearly doubled to more than 1 million since 1990. Some of the fastest growth has unfolded along the Front Range, where the number
of large, high-severity fires has increased in recent decades.
Texas now has 3.2 million homes in the WUI and saw the fastest growth of any state over the past decade. While some of Texas’ most destructive wildfires have been in forests, many of its wildlands consist of grasses and shrubs, where fires can spread
more rapidly and often damage more homes. Last year, the state climatologist’s office warned that wildfire risks were growing as the state dries out.
The rapid growth of housing in flammable areas is a key reason wildfires have become more destructive over time. Not only are the homes themselves more likely to burn, but when more people live near forests and grasslands, there’s also a greater chance
that fires will start in the first place. While wildfires are often sparked by lightning, humans themselves cause the vast majority of ignitions, often by accident: a cigarette thrown out the window, or a vehicle’s muffler setting fire to dry grass.
More homes in fire-prone territory also increases the demand for firefighting in often difficult terrain, which can stretch fire suppression resources thin and, in turn, lead to a dangerous build-up of vegetation in areas that experts say would benefit
from burning at low levels more frequently. Wildfires have long been a natural part of the Western landscape and only become disasters when humans are in the path.
“The more homes we have in the wildlands, the more people we have to protect, more people that need to be evacuated,” said Miranda H. Mockrin, a research scientist at the United States Forest Service, who worked on the new study. “It becomes more
of a challenge.”
The researchers estimated that 136,000 homes were within the perimeter of Western wildfires in the 2010s, compared with fewer than 31,000 in the 1990s. Some of that increase occurred because fires are burning ever-larger amounts of territory. But about
one-quarter of the homes threatened by wildfires over the past decade did not exist in the 1990s, indicating that housing growth in wildfire territory was a key driver of the rise in fire danger.
“We have this sort of two-headed monster,” said Stephen M. Strader, a disaster scientist at Villanova University, who was not involved in the research. “One side is a changing environment, and the atmosphere being altered by climate change. But if
you look at that in isolation you forget about the other side: Society is changing, our cities are changing, our land is changing.”
“All these conditions coming together,” he said, “creates a more disaster-prone society.”
While the new data only runs through 2020, a separate report by Redfin, the Seattle-based real estate brokerage, found that demand for homes in fire-prone areas has continued to grow since the coronavirus pandemic began, as remote work allowed Americans
to move further from job centers.
Wildfire experts say it is unlikely that Western states will ever be able to stop all growth in the wildland-urban interface. But alongside efforts to improve forest management in these areas, governments could impose tighter restrictions on future
development to ensure communities are better protected against fire dangers that are unavoidable.
“So much of the West is wildfire-prone that it’s a non-starter to say you shouldn’t live anywhere there’s a risk,” said Molly Mowery, executive director of the Community Wildfire Planning Center, a Denver-based nonprofit. “It’s much more
productive to focus on what we can do to protect our homes and neighborhoods when fire does arrive.”
Such protections include creating more “defensible space” around homes and neighborhoods, cleared of brush and vegetation, to keep blazes at a distance. It would mean building houses so they are better protected against burning embers carried by the
wind, which often cause structural fires by blowing into homes through vents in the eaves or sides.
In 2008, California adopted some of the strictest rules in the country for new homes in high-risk fire areas, requiring developers to use fire-resistant materials and to provide access to water for firefighters. Those rules can make a difference. After
the Camp Fire, one analysis found that about 51 percent of the 350 single-family homes in Paradise built to the new codes escaped damage, compared with just 18 percent of the 12,100 homes built before the standards.
Most Western states don’t have statewide codes, however, and it is usually up to local governments to enforce their own standards. In 2019, Austin, Tex., one of the fastest-growing cities in the country, took matters into its own hands, adopting
stringent rules for new homes in the WUI that require, for instance, noncombustible screens over attic vents and safe storage of propane tanks.
Yet building codes for new construction only go so far, because they don’t address the millions of vulnerable homes that have already been built. Properly protecting an existing home can be expensive, costing up to $27,000, which means that governments
may need to step in to help.
For now, progress remains patchy. In many regions, developers have resisted new regulations, warning that they could drive up housing costs. And even after communities suffer from a wildfire, the pressure to rebuild quickly, and without new requirements,
is intense.
“Too many places are still operating under the mind-set that they can keep building in high-risk areas and if there’s a wildfire, the firefighters will come and save their homes,” said Kimiko Barrett, a wildfire researcher at Headwaters Economics,
a nonprofit research group. “Once we realize that we’re not going to stop every last fire, we can start thinking about how to live with wildfire.”
There are signs that things may be changing. After the Marshall Fire in Boulder in late 2021 destroyed more than 1,000 buildings, lawmakers in Colorado began discussing new statewide codes, though they have yet to adopt any. And over the past decade,
California has actually added more homes outside the WUI than within it. Dr. Radeloff said it was still too early to tell whether that’s a sign of changing attitudes toward fire risk.
“It’s a beautiful place to live,” said Dr. Radeloff of the wildland-urban interface. “But as a society, we really have to wrap our heads around what living so close to nature really entails.”
https://www.nytimes.com/interactive/2022/09/09/climate/growing-wildfire-risk-homes.html
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