Worst Fires in California’s History? Some Clarifications

Lack of defensible space around homes a major reason for extent of destruction, says wildfire ecologist

On Monday, journalist, author, and author and environmental activist Bill McKibben tweeted data from CalFire regarding the top 20 most destructive fires in California. He wrote:

“Five of the twenty worst fires in CA history have come since September. Hot new world.” 

photo of twitter accountImage from Twitter On Monday Bill McKibben tweeted about the fires that have been raging across California this year.

When I came across the tweet, I immediately grabbed a screenshot and sent it off to Earth Island’s own wildfire expert — ecologist Chad Hason, director of John Muir Project.

Is McKibben’s interpretation accurate? I asked. What exactly do these figures mean? 

Here’s the explanation that Hanson emailed back, which I’m reproducing with some edits here. It’s worth reading through during this ongoing fire season in the West, when there are so many numbers and confusing data and wildfire causes being cited in the media. 

“He is talking about the number of homes burned, which may be accurate. He is not referring to fire size, although the Thomas fire is large — but the others not so much. 

“This year there was not much wildland fire in the mountain forests, since we had a big winter in 2016-2017. But the high levels of winter and spring precipitation allowed a lot of grass to grow, and these fires are mostly driven by grass, and shrubs in low elevations near population centers. 

“Because there is poor monitoring and enforcement for defensible space in most California counties, and because few counties have meaningful requirements with regards to fire-safe roofing and siding materials, severe impacts on communities can be expected in such circumstances.” 

Los Angeles is an exception in this regard, Hanson says. Which is why during the La Tuna fire in September, though there were more than 700 homes within the fire perimeter, only 5 burned.

Hanson has explained before that while a volatile combination of higher temperatures, low rainfall, and dry weather — all in part connected to climate change — is making extreme fire weather more frequent in the West than in the past few decades, that’s not the main reason that certain fires are so damaging.

He says we can avoid the kind of destruction the current fires have wrecked on our homes and communities, “but only if we stop focusing resources on backcountry fire suppression and logging, and instead focus on protecting communities.”

Read our in-depth feature, “The War Against Wildfire” to learn more about the ecological role of forest fires and the futility of many current fire control methods.

For more information on creating a defensible space around your home go here.

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