John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
As wildfires rage in California’s wine country, the scene is set for a recurrence of Oakland’s devastating 1991 blaze.
Right before deadly fires broke out last weekend in California’s wine country, John Radke, a Berkeley professor who specializes in fire modeling and environmental planning, tossed and turned in bed. “I couldn’t sleep all Sunday night,” he recalls. “I thought, This is 1991 all over again. I could feel it—the conditions were all the same.”
Radke is referring to the 1991 Oakland hills firestorm, a calamitous and swift-moving blaze that killed 25 people, destroyed roughly 3,000 homes and 2,000 vehicles, and caused an incredible $1.5 billion in damages. His hunch proved correct, at least for the North Bay: Intense fires flared up in Sonoma, Napa, and elsewhere, fueled by powerful winds, bone-dry humidity, and drought-affected vegetation. The latest toll of the still-smoldering catastrophe is more than 30 dead and about 450 missing, with ongoing mandatory evacuations.
Immediately after the outbreak, the National Weather Service drew comparisons to the 1991 disaster. “For the last 25 years or so the Oakland hills fire has been the seminal fire event that was seared into Bay Area residents’ psyche,” the agency wrote. “For the current generation of North Bay residents, today’s firestorm will leave an indelible scar and for years to come we will all recall the Columbus Day firestorm.”
As the wine-country conflagrations continue to paint Bay Area skies yellow-brown—with white ashes raining on cars—folks in Oakland are reminded that California’s fire season is fully alive and potentially vicious. Indeed, the 1991 firestorm exploded on October 20, a date rolling around next week, and conditions are highly favorable for fire with tons of dried-out plant life and weather so windy and arid forecasters have declared red-flag warnings in the neighboring hills. So what are the odds one of the hippest, highest-rent cities in the United States will suffer another devastating blaze in the near future?
“We likely will,” says Radke, who’s trained in firefighting school and is now working on a project about how major outbreaks could affect the transportation-fuel sector. “We can fight it better, but the fuels are there.”
To understand the risk of these “fuels,” one just needs to travel through the steep, winding hills overshadowing Oakland and Berkeley. A warm summer and the region’s Mediterranean climate—the same climate that perennially parches the now fire-ravaged North Bay—have left the land littered with dry brushes ringing trees. When ignited, these airy brushes act like flame ladders up into the canopy, where fire can find leaves and branches, intensify, and spew embers onto other vegetation and structures. And these aren’t just any trees: The hills are rife with natural fire-starters.
Take the majestic Monterey pine. It grows for 60 or 70 years and then dies, either from insect damage or falling over, becoming a 90-foot-long Duraflame log. Then there’s juniper. “People love it—many of the homes up there have juniper out front,” says Radke. “In 1991, there was a 20 mph wind and there were 35-foot flame lengths being measured off of junipers, because underneath that beautiful green, velvety surface is usually dead wood or dead needles.”
Perhaps most pernicious of these plants is eucalyptus, a sky-kissing specimen that California tycoons imported for timber. Eucalyptus trees are notable for seedpods that look like strange, mechanical nuts and are extremely oily. “When there’s a firestorm, it’s creating its own weather, so you’ve got this uplifting of heat and the pods will go right up into the air,” says Radke. “When they come down they’re actually on fire, so it’s a bit like someone raining Molotov cocktails on you.”
When enough trees catch fire, the immense amount of radiated heat makes control efforts nearly impossible. “If a fire gets above a thousand BTUs or up in that range, and has long flame lengths, then firefighters are going to pull out,” Radke says. “The incident commander’s going to say, ‘My firefighters are at risk, and I can’t risk the death of a firefighter.’ They’re going to pull back and try to form a containment line somewhere else that might be less risky.”
Before the 1991 fire, the Oakland hills were densely packed with trees hugging properties, creating a charming, bucolic atmosphere akin to Robin Hood’s Sherwood Forest. When the firestorm was at its peak, the trees were fueling the very flames that destroyed the homes of the tree-enjoyers. But after the ashes cooled, to the chagrin of fire experts, residents who stayed to rebuild started planting more trees.
“It looked pretty safe back then, but now when you look at it those trees have grown up,” Radke says. “They’re trying to gain Sherwood Forest back, I guess. I don’t mean that in a spiteful way, it’s just that everyone wants to live in a beautiful, forested area.”
To this day, some locals remain fiercely protective of their beloved green canopy. In 2015, for example, a group of neighbors successfully sued FEMA, Oakland, and the University of California, Berkeley, to prevent them from cutting down fire-prone trees like eucalyptus and pine. “It’s difficult to get people to realize they shouldn’t be nurturing those plants,” says Radke. “They should be killing them off.”
Would a modern firestorm be as crushing as 1991’s inferno? Probably not. Homes that sprouted up after were built with caution in mind, utilizing fire-resistant siding and eschewing wooden roofs and open eaves. Many were also built much larger—developers use every opportunity to pack in square footage, even after a disaster—which means there’s less room on the property for trees. And the firefighting community has evolved greatly after 1991, improving its mutual cooperation and response time, upgrading radio equipment and standardizing fire hydrants, and training personnel in wildland firefighting in steep, plant-strewn terrain (back in the day, some responders had only battled fires on city blocks).
Still, Radke believes there’s a blaze coming, and it won’t take much to set it off. The 1991 calamity arose from a fire people had presumed extinguished. Witnesses recall that a “sole ember blew into a tree just outside the burn area, and the tree exploded into flame.” A fire might arise from a tossed-out cigarette or a red-hot car part falling onto a road shoulder; a bird colliding with power lines and plummeting, smoldering, into dry grass; or an arsonist like the guy who, steaming over a road-rage incident, allegedly started a fire in the hills this August. It could even surge from something as innocuous as power lines. In warm weather these lines stretch out, and when the winds blow they can swing and touch each other, showering sparks onto the ground.
Locals could reduce the firestorm chances by properly managing their vegetation. Regulations in parts of the hills require landowners to clear a 30-foot “safety zone” around homes, though not everybody does. They could also chop down troublesome trees like eucalyptus, though Radke admits the cost, which can run as high as $5,000 per tree, is prohibitive for many people. He suggests governments or insurance agencies could perhaps offer tax incentives or other schemes—giving residents a rebate if they get a problem tree assessed for a felling, for instance.
It’s difficult for fire managers to convince people to mitigate a fire hazard like a poorly placed tree, Radke says. In the manager’s mind, they’re getting a huge insurance against a blaze; in the property owner’s view, they’re shelling out $5,000 to uglify a yard. But consider the alternative. “Those people in the North Bay, they’re kicking themselves now,” Radke says. “They’d be willing to go into the past and give you $10,000, because they lost everything.”