Wildfire risk rises with 43 million U.S. homes near land susceptible to blazes

Doyle Rice | USA TODAY

Show Caption Hide Caption Wildfires sweeping Southern California put millions on edge Six separate wildfires are threatening millions of people in one of the country's most densely populated areas.

"It's all gone," Jack O'Callaghan said in October as he stood in the charred rubble of what was his home in Glen Allen, Calif., following a deadly wildfire.

For folks like O'Callaghan, living in paradise has a cost: Americans are choosing to live in areas that are increasingly prone to devastating wildfires, a new study suggests.

Overall, as of 2010, some 43 million homes were located in what scientists call the "wildland-urban interface," defined as the area where residential homes are built on or near wildland vegetation, such as trees and shrubs.

Twenty years earlier, 31 million homes were located in those areas for a whopping increase of 41%.

Last year was a particularly destructive and costly year for wildfires, with 10 million acres burned and a record $2 billion to fight the blazes. Five of California's 20 worst wildfires on record scorched the state in 2017.

When combined with the threat of global warming, Americans choosing to live near forests is expected to lead to more severe wildfire seasons.

Living near the woods poses two problems when it comes to wildfires, according to the study published in the Proceedings of the National Academy of Sciences, a peer-reviewed journal. First, more wildfires are likely to occur due to people accidentally — and purposefully — igniting the blazes. Second, the wildfires that flare up pose a greater risk to lives and homes because they are harder to fight. And letting natural fires burn becomes impossible.

“We've seen that many wildfires are caused by people living in close proximity to forests and wildlands," said study lead author Volker Radeloff, an ecologist at the University of Wisconsin.

And when those fires spread, "they are much harder to fight when people are living there, because lives are at risk, and because properties have to be protected,” said Radeloff, who wants to use the current study to understand how that risk developed over time.

Surprisingly, while western fires are often the most newsworthy, the study found that much of the growth of the wildland-urban interface has been in the densely populated eastern U.S., as well as the southern Plains states of Texas and Oklahoma.

Big increases were also reported in the West. However, Radeloff said that in the West, a larger portion of public lands are unavailable for development. Also, mountainous areas and reduced access to water can limit the growth homes in that region.

The researchers recommend several land management practices to limit the negative effects of expanding wildland-urban interface, such as vegetation management, use of appropriate building materials and zoning regulations.

“There's a lot that can be done," Radeloff said. "We better start doing it or otherwise we will have news like what we had last fall again and again," referring to the ferocious wildfires that swept through densely populated regions of northern California.