Oakland Hills Fire Archives

Data shows building codes can reduce vulnerability of homes in wildfires

Bill GabbertJanuary 30, 2022January 30, 2022UncategorizedCalifornia, FireWise, home ignition zone, Oakland Hills Fire, Tunnel Fire10 Comments

Slave lake burned homes — Burned homes in Slave Lake. May 16, 2011. Alberta, Canada. CTV.

Researchers have found that building codes based on lessons learned during the deadly 1991 Tunnel Fire in the Oakland Hills of California can reduce the vulnerability of homes to wildfires.

In a paper titled Mandatory vs. voluntary adaptation to natural disasters: the case of U.S. Wildfires, authors Patrick W. Baylis and Judson Boomhower describe how they scoured property and wildfire records to identify which homes were constructed under building codes requiring enhanced resistance to wildfires.

Chapter 7A of the California Building Code which went into effect in 2008 requires certain fire resistance measures, including exterior construction materials used for roof coverings, vents, exterior walls, and decks. It applies to new construction of residential and commercial buildings in designated fire hazard severity zones.

The researchers discovered that a 2008 or newer home is about 16 percentage points (40%) less likely to be destroyed than a 1990 home experiencing an identical wildfire exposure. There is strong evidence, they concluded, that these effects are due to state and local building code changes – first after the deadly 1991 Oakland Firestorm, and again with the strengthening of wildfire codes in 2008. The observed vintage effects are highly nonlinear, appearing immediately for homes built after building code changes. There are no similar effects in areas of California not subject to these codes or in other states that lack wildfire codes.

Their findings are similar to those in a paper published October 4, 2021 in which researchers analyzed the structures that were destroyed and those that survived the Camp Fire that ran through the city of Paradise, California in 2018. They considered at least four primary characteristics of structures:

Were they built before or after the adoption in 2008 of Chapter 7A of the California Building Code.
Distance to nearest destroyed structure.
Number of structures destroyed within 100 meters.
Pre-fire overstory tree canopy within 100 meters

They found that the last three criteria were the strongest predictors of survival. Homes more than 18 meters (59 feet) from a destroyed structure and with less than 53 percent pre-fire overstory canopy within 30 to 100 meters (98 to 328 feet) survived at a substantially higher rate than homes in closer proximity to a destroyed structure or in areas with higher pre-fire overstory canopy. Most fire damage to surviving homes appeared to result from radiant heat from nearby burning structures or flame impingement from the ignition of near-home combustible materials. The researchers concluded that building and vegetation modifications are possible that would substantially improve outcomes. Among those include improvements to windows and siding in closest proximity to neighboring structures, treatment of wildland fuels, and eliminating near-home combustibles, especially within 1.5 meters of the structure.

(The video below was shot December 31, 2021, the day after the Marshall Fire destroyed more than 1,000 homes in Boulder County, Colorado. Notice that most of the surviving homes seen in the video had fewer homes in close proximity.)

The authors noted that while Chapter 7a includes requirements not found in many building codes, a few other codes are more complete incorporating multiple construction classes based on anticipated radiant heat, flame, and ember exposure levels. For example Chapter 7A does not consider the interaction between components such as siding, window, and the under-eave area on an exterior wall.

California is embarking on a pilot project in which owners of vulnerable homes in lower income neighborhoods will be given grants up to $40,000 to retrofit the structures, making them more resistant to wildfires.

Home Ignition Zone

This data helps to illustrate that the condition and characteristics of the Home Ignition Zone should be an extremely high priority in preventing structures from burning as a wildfire approaches.

There is an opportunity for much needed improvement in both current building codes and how we live in wildfire prone WUI areas.

Thanks and a tip of the hat go out to Gerald.

Sierra Club argues against FEMA’s plan for the eucalyptus trees in Oakland’s East Bay Hills

Bill GabbertMay 29, 2015May 29, 2015UncategorizedCalifornia, eucalyptus, Oakland Hills Fire, Tunnel Fire

The Sierra Club and the Sustainability, Parks, Recycling and Wildlife Legal Defense Fund (SPRAWLDEF) filed suit on May 26 over plans by the Federal Emergency Management Agency (FEMA) to fund a vegetation-management program in the East Bay hills that would increase fire hazards, threaten endangered species and native wildlife, and increase the financial burden on taxpayers.

“The best way forward is to promote native vegetation that is less flammable and encourages healthy ecosystems and greater biodiversity,” said Sierra Club San Francisco Bay Chapter director Michelle Myers. “That’s a win-win for the environment and for homeowners who want to feel secure that they won’t lose their homes in another Great Fire like the one we lived through in 1991. Unfortunately, FEMA’s approach isn’t in line with the priorities of fire safety and habitat restoration.”

FEMA has over $5.5 million in grant money to disburse for vegetation management in the East Bay Hills from Richmond to San Leandro. These areas contain thousands of acres of highly flammable eucalyptus and non-native pines, which choke out more fire-resistant natives like oaks, bays, and laurel. Flying in the face of the best science and land-management practice, the Sierra Club said, FEMA has signaled its intention to fund a plan to thin flammable non-natives, rather than remove them entirely. The Sierra Club / SPRAWLDEF suit contents that this is the wrong approach.

The Sierra Club and other environmental groups including the Claremont Conservancy, the Golden Gate Audubon Society, and the California Native Plant Society have all advocated for removing all of the flammable eucalyptus and pine trees over time so that less-flammable native habitat can reclaim those areas. In contrast to clearcutting, this approach calls for removing eucalyptus in phases, so that native trees — which cannot grow to full size underneath the eucalyptus canopy — are able to thrive. Mere thinning of eucalyptus and pine plantations in fact denudes hillsides to an even greater extent, as it requires the clearing of native plants in the understory.

Thanks and a tip of the hat go out to Barbara.

A view of the potential in the Oakland Hills through the eyes of an Australian

Bill GabbertApril 23, 2014April 23, 2014UncategorizedCalifornia, eucalyptus, Oakland Hills Fire, Tunnel Fire2 Comments

1991 Tunnel Fire. Screen shot from the Oakland Wildfire Prevention Assessment District video below.

The Oakland Hills, which was devastated by the Tunnel Fire in 1991, has some things in common with Australia. The most obvious is the eucalyptus trees, a species imported from down under. The volatile highly combustible oil in the leaves causes fires to burn rapidly under them and through the tree crowns. The eucalyptus contributed to the spread of the Tunnel fire, which killed 25 people, injured 106 residents, and burned 3,354 homes.

Christine Erikson has written about fires in Australia and authored a book titled Gender and Wildfire: Landscapes of Uncertainty. During a visit to the United States in which she made presentations at conferences, she toured the Oakland Hills. Below is an excerpt from an article she wrote about the experience:

…I felt right at home amongst the swaying eucalyptus trees, which despite much controversy still stand tall in the Oakland Hills. Yet, unlike the ‘Prepare, Stay and Defend or Leave Early’ mantra that is associated with living in eucalyptus dominated (i.e. fire-prone) landscapes in Australia, it was the continuing absence of an official policy on how to better prepare residents for future wildfires in the Oakland Hill that loomed large for me during the fieldtrip. What should residents do if evacuation is not a feasible option in the future? How can residents prepare so a similar disaster is prevented? These questions linger like ghosts at every twist and turn of the narrow, winding mountain roads where smoke, embers and flames resulted in accidents and panic that fatally trapped residents in 1991.

This ghostly presence clearly has not escaped the attention of the local Oakland Fire Department. In addition to official projects, the Department is now “unofficially” advising residents on what they can do to increase their chances of survival. Preparing properties in the Oakland Hills, however, is easier said than done. The recommended ten-metre clearance around residential homes is unrealistic in most of these neighbourhoods dominated by quarter acre blocks. A representative from the Oakland Hills Wildfire Prevention program pointed out that when these two-dimensional blocks are considered three-dimensionally, thus taking into consideration the considerable hill slope, these blocks become one-acre properties in need of defence. He furthermore spoke to the frustration of local building-, planning- and fire-codes not supporting each other. The statutory law of developing a given property, for example, sits within a planning code that does not necessarily follow local fire safety recommendations.

The video below, produced by the Oakland Wildfire Prevention Assessment District, discusses the 1991 Tunnel fire and what the city is doing now to mitigate the vulnerability the area has to the next wildfire.

Eucalyptus and fire

Bill GabbertMarch 3, 2014April 23, 2014UncategorizedAustralia, eucalyptus, Oakland Hills Fire, Tunnel Fire

Wildland firefighters in Australia and in some areas of California are very familiar with eucalyptus trees. They are native and very common in Australia and are planted as ornamentals in the United States. The leaves produce a volatile highly combustible oil, and the ground beneath the trees is covered with large amounts of litter which is high in phenolics, preventing its breakdown by fungi. Wildfires burn rapidly under them and through the tree crowns. It has been estimated that other than the 3,000+ homes that burned in the 1991 Oakland Hills Fire in California, about 70 percent of the energy released was through the combustion of eucalyptus.

Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”.

Jon Henley, a reporter who covered the numerous large bushfires a year ago in Australia, has written a book about fire down under, titled “Firestorm: Surviving the Tasmanian bushfire”. Below is an excerpt:

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“…Gum trees, as eucalypts are known, ‘are like weeds that come up on bombed-out blocks’, adds Jamie Kirkpatrick, professor of geography and environmental studies at the university. ‘They’re fantastically fast growers and great colonisers, but not great competitors.’

Eucalypts typically let through a lot of light, allowing other vegetation types such as scrub and grass to grow beneath them. They can live for maybe 700 years. But they won’t regenerate, Kirkpatrick explains, if what is growing beneath them over the years becomes too dense. Most eucalypt species, therefore — there are more than 600 in Australia, between 30 and 40 in Tasmania — have evolved traits that allow them to survive and prosper in the fires that will clear that undergrowth.

Some, like the mighty, 100-metre-tall Eucalyptus regnans — also known as the mountain ash, stringy gum or Tasmanian oak — hold their seeds inside small, hard capsules; a fire will instantly trigger a massive drop of seeds to the newly fertilised ground.

The myriad bright green buds that sprout spectacularly from the trunks of other eucalypts in the aftermath of a big fire are another kind of regeneration mechanism, bursting through the scorched and blackened bark within weeks of a blaze.

Within five or six years, ‘a burned forest will be looking pretty good’, Kirkpatrick says. ‘And a large proportion of Tasmania’s flora fits into this fire ecology. Pea plants, wattles — their germination is stimulated by heat and smoke. Fire is really, really important in Tasmania.’

At the centre of it all, though, is the eucalypt. Because these trees do not just resist fire, they actively encourage it. ‘They withstand fire, they need fire; to some extent, they create fire,’ Bowman says. ‘The leaves, the bark, don’t decompose. They’re highly, highly flammable. And on a hot day, you can smell their oils.’

The bark and leaves of eucalypts seem almost made to promote fire. Some are known as stringyor candle-barks: long, easily lit strips hang loosely off their trunks and, once alight, whirl blazing up into the flammable canopy above, or are carried by the wind many kilometres ahead of a fire to speed its advance.”

This is an edited extract from Firestorm: Surviving the Tasmanian bushfire by Jon Henley (Guardian Shorts £1.99 / $2.99)

Get it from Amazon Kindle or directly from Guardian Shorts.

20 years later, potential for another Oakland Hills fire?

Bill GabbertOctober 20, 2011August 25, 2019UncategorizedCalifornia, eucalyptus, Oakland Hills Fire, Tunnel Fire

It was 20 years ago today that a rapidly moving fire in the Oakland Hills east of San Francisco ravaged a community. Here is the way we describe it in our Infamous Fires Around the World document:

The “Tunnel Fire”, commonly referred to as the Oakland Hills fire or East Bay Hills fire, occurred on Sunday October 20, 1991. The fire killed 25 people (23 civilians, 1 police officer, and 1 firefighter), injured 150, and destroyed 2,449 single-family dwellings and 437 apartment and condominium units. Eleven of the fire victims died in traffic jams on Charing Cross Road while evacuating. Eight others died on narrow streets in the same area. The economic loss has been estimated at $1.5 billion.

The fire started when an ember from a grass fire the previous day blew beyond the fire hoses that were still on the fire perimeter and started a new fire. Houses, like the vegetation, have grown back and some of the residents that lived through the 1991 fire are worried when they look around and see that some of their new neighbors are not doing as much as they could to prevent another disaster.

Here is an excerpt from an interesting article in the Mercury News:

As autumn returned and the mercury hovered in the 90s in the Oakland hills, Milt Brown started to feel anxious.

Twenty years ago, on a scorching, wind-whipped day, he lost two houses in one of the nation’s deadliest and most destructive urban wildfires, an inferno that jumped two freeways, destroyed more than 3,800 homes and killed 25 people, including the Browns’ former baby sitter.

Although he tries not to dwell on the horrible memories — or the chance of another devastating blaze — Brown and other survivors of the Oakland hills fire worry that the painful lessons of that day are being forgotten. Or worse, they are being ignored by the many newer residents who didn’t experience firsthand the hell of Oct. 20, 1991. Even the subtlest signs of danger make him nervous.

“I’m looking at the two houses below me and the branches are touching the house,” Brown said from his perch on Buckingham Boulevard — less than a minute’s walk from where the fire erupted on a hot Sunday morning. “I’m in a box canyon. If someone throws a match in there it will set the whole block off.”

But it isn’t just those who lived through the Oakland hills fire who are anxious about what they fear is a growing complacency that has built up alongside the stately homes in these steep, once-woodsy enclaves. Fire officials say that time has not only given rise to dense stands of fast-growing and fire-susceptible eucalyptus on public lands, it has also given vegetation on private property throughout the hills 20 years to mature. It often takes a second notice before residents take heed and clear a defensible space around their homes to protect it from fire.

Thanks go out to Dick

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Thanks and a tip of the hat go out to Barbara.

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