Science

Living on the Edge

Just as coastal communities must learn to live with hurricanes, communities that edge up against forests are going to have to learn to live with fire.

Scorched power lines and a sign reading high voltage.
The remains of scorched power lines lie at the driveway of a burned residence in Paradise, California, on Nov. 9.
Josh Edelson/AFP/Getty Images

It’s hard to look at the images of what used to be Paradise. On Nov. 8, California’s Camp Fire tore through the Sierra Nevada foothills town of 27,000 people with little advance warning. It destroyed homes, incinerated cars—many of which were abandoned on roads that had became gridlocked by fleeing residents—and left a death toll of 77 people and climbing. Nearly 1,000 remain unaccounted for. But if you look closely at photos and video of the aftermath, you’ll notice something surprising. The buildings are gone, but most of the trees are still standing—many with their leaves or needles intact.

The Camp Fire is generally referred to as a forest fire or, to use the term preferred by firefighting professionals, a wildfire. As the name suggests, wildfires are mostly natural phenomena—even when initially triggered by humans—moving through grasslands, scrub, and forest, consuming the biomass in their paths, especially litter and deadwood. Visiting the disaster area, President Donald Trump blamed poor forestry practices and suggested California’s forests should be managed more like Finland’s where they spend “a lot of time on raking and cleaning.”

But the photos tell a different story. Within Paradise itself, the main fuel feeding the fire wasn’t trees, nor the underbrush Trump suggested should have been raked up. It was buildings. The forest fire became an infrastructure fire. Fire researchers Faith Kearns and Max Moritz describe what can happen when a wildfire approaches a suburban neighborhood during the high-wind conditions common during the California fall: First, a “storm of burning embers” will shower the neighborhood, setting some structures on fire. “Under the worst circumstances, wind driven home-to-home fire spread then occurs, causing risky, fast-moving ‘urban conflagrations’ that can be almost impossible to stop and extremely dangerous to evacuate.” The town of Paradise didn’t just experience a fast-moving wildfire, its own layout, building designs, and city management turned that fire into something even scarier.

At first glance, the cause of the Camp Fire seems obvious: Sparks from a power line ignited a brush fire, which grew and grew as high winds drove it toward the town (there were also reports of a possible second ignition point). Pacific Gas and Electric, the regional utility, is already facing extensive lawsuits and the threat of financial liabilities large enough to bankrupt the company. And yet, like almost every disaster that kills large numbers of people and damages communities, the causes of the tragedy in Paradise are more complex than it first appears. The failure of the power line was the precipitating factor, but other factors came into play as well: zoning laws and living patterns, building codes and the types of construction materials used, possibly even the forestry management practices Trump inelegantly referenced. (Many residents of Finland got a chuckle out of Trump’s “raking and cleaning” comment, but Trump isn’t alone in calling for more aggressive management of California woodlands.)

A number of environmental, political, and economic trends converged in Butte County in just a few hours on Nov. 8 to spark this fire. But the tragedy was the result of many longer-term decisions, decades in the making.

Paradise sits in the picturesque foothills of the Sierra Nevada range. Its streets bump up against the forest. The surrounding Butte County is less densely populated but still has many homes on lots of between 1 to 5 acres. (Some 46,000 people were displaced by the fire overall.) That makes Butte County a prime example of what planners call the wildland-urban interface. A recent Department of Agriculture study defined the WUI as “the area where structures and other human development meet or intermingle with undeveloped wildland.” The report estimated that nearly a third of California’s residents lived in such regions in 2010. And their numbers are growing.

It’s easy to see why. These are lovely places to live, attractive to longtime residents as well as retirees and people moving out of cities. But they are also dangerous, especially in California. The state is subject to several conditions that make fires particularly threatening. One is drought. California summers have always been dry, but records show that they’ve been getting hotter and dryer. Fire season is getting longer. Climate models show that that trend is likely to get worse.

Another is wind. Each fall, hot, dry air flows westward from the state’s higher elevations toward the coast. These Santa Ana or “diablo” winds can blow at high speeds for days on end. (On the morning of the Camp Fire, wind speeds as high as 72 miles per hour were recorded.) Like a giant hair dryer, the wind desiccates everything in its path. The night before the fire, local meteorologist Rob Elvington warned: “Worse than no rain is negative rain.” The winds were literally sucking moisture out of the ground.

Those hot, dry conditions make fires terrifyingly easy to start—a hot car muffler, a cigarette ash, a downed power line, almost anything can do it. And the wind makes them almost impossible to stop. As it barreled toward Paradise, the Camp Fire grew at the rate of roughly 80 football fields per minute. “California is a special case,” fire historian Stephen J. Pyne recently wrote in Slate. “It’s a place that nature built to burn, often explosively.” Even if no one lived in them, California’s hills would burn regularly, Pyne notes. But humans and their infrastructure make the problem worse.

One of the biggest risk factors is electric power. Utilities like PG&E don’t have the option of not serving rural or semirural residents. And every power line that crosses dry, flammable terrain could spark a wildfire. The culprit in these cases is, once again, the interplay between human-built infrastructure and the natural environment. Vegetation is constantly growing in the corridors, and if a tree falls on a line, or merely touches it, that can cause a short circuit that might spark a fire.

Cal Fire, the California fire management agency, estimates that problems with power lines caused at least 17 major wildfires in Northern California last year. Under an unusual feature of California law known as “inverse condemnation,” a utility can be forced to pay damages for fires that involve its equipment, even if the company hasn’t been proven negligent in its operations. Even before the massive Camp Fire, PG&E announced that it expects its liabilities from 2017’s large wine-country fires to exceed $2.5 billion. (California Gov. Jerry Brown recently signed a bill offering some financial relief to utilities grappling with wildfire costs, but it did not do away with inverse condemnation.)

As more and more people move into wildland-urban zones, these new arrivals will need to be served with electric power. Which means that, not only will there be more people living in the zones threatened by wildfires, but more power lines will need to be built, increasing the risk of fires. Disaster researchers call this the expanding bull’s-eye effect. Also, as more people move into vulnerable regions—and then build expensive infrastructure in those areas—the costs of natural disasters increase. This effect has been shown dramatically in coastal areas such as Houston that have seen the damage estimates associated with hurricanes skyrocket. The expanding bull’s-eye means the costs of rebuilding will keep climbing even if the frequency and severity of natural disasters doesn’t change.

So, California’s fire country faces a double-barreled threat: More lives and infrastructure lie in the path of potential fires than ever before. And the fires are getting bigger. That combination explains why 6 out of the 10 most destructive fires in California history have occurred in the past three years.

So far, California is not doing much to discourage people from moving into its danger zones. Moritz, Naomi Tague, and Sarah Anderson, researchers at the University of California, Santa Barbara, maintain that “people must begin to pay the costs for living in fire-prone landscapes.” They argue that currently, “the relative lack of disincentives to develop in risky areas—for example, expecting state and federal payments for [fire] suppression and losses—ensures that local decisions will continue to promote disasters for which we all pay.” (Disaster experts make a similar argument about how federal flood insurance and other programs encourage people to live in hurricane-prone areas.) One financial analyst who works closely with California utilities believes the inverse condemnation rule is part of this problem: “These communities are very dangerous to supply power to,” he says. “But the utility is forced to carry all the risk. They can’t charge their customers a premium for fire risk.”

Of course, when fires do occur, the residents of these areas suffer the most. The question is how to provide the right incentives for people so that we limit the chances of this happening again. Looking ahead, “We need to ensure that prospective homeowners can make informed decisions about the risks they face in the WUI,” Moritz, Tague, and Anderson say.

What else can be done? Building and zoning codes can be changed to make towns less fire prone. Homes that are built or retrofitted with fireproof materials—and landscaped to keep shrubbery away from structures—can usually survive typical wildfires. In new developments, homes can be clustered and surrounded by fire-resistant buffer zones, such as orchards. And, no matter how well designed, communities in fire zones need realistic evacuation plans and better emergency communications. (Poor communications and inadequate evacuation planning in the face of the speed a fire could move at were among the many failures in Paradise.)

There’s even a grain of truth to Trump’s comments that better forest management can reduce the ferocity of wildfires, though it’s not clear it would have helped in the case of the Camp Fire. The Santa Barbara researchers recommend increasing “fuel management such as controlled burns, vegetation clearing, forest thinning, and fire breaks.”

But no amount of fire-proofing or woodland management is going to eliminate fires.

If global warming models hold true, fire seasons are going to be hotter and last longer. Just as people in coastal areas need to adapt to hurricanes, residents of fire country need to learn to live with fire. In both cases, the states and the federal government need to reconsider policies that encourage people to move into these vulnerable areas. It’s easy to see why people love living in mountain foothills and forests—just as it’s easy to see why they love living on beaches. But overdevelopment of fire-prone landscapes means multiplying the inherent hazards of these regions. People need to accept that the problem isn’t just fire—it’s us.