January 12, 2001
Project Shields Berkeley Lab From Wildfire; Article by Jeffery Kahn
Berkeley Lab Science Beat

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Like a log in a hearth, Berkeley Lab is lodged within a hillside landscape that repeatedly has been overrun by conflagration. Diablo wind-driven wildland fires burned sections of the East Bay Hills in 1923, 1931, 1933, 1937, 1940, 1946, 1955, 1960, 1961, 1968, 1970, 1980, and 1991.

A decade ago, 25 people died, 3,403 structures were destroyed, and $1.5 billion in property was vaporized. Only by whim of the wind did the Laboratory escape the 1991 firestorm.

The Claremont Hotel somehow survived the 1991 firestorm

Since that date, a little noticed yet intense battle has been waged here to make sure this laboratory survives the next fire and averts its flash metamorphosis into a fire-gutted ruin.

Says lab emergency manager Don Bell, "What we have done here in the last nine years is unbelievable. It is the difference between night and day."

Adds Rich McClure, the Facilities Department planner who has spearheaded the effort, "One day there will be another fire. There is no question about it. The vegetation will burn. The question is whether it will take out buildings and cost lives. Six years into our project, I can say that wildland fire no longer can cause major damage here, that most of the Lab can survive a wildland fire. And in two years when the initial hazard reduction effort is completed, we anticipate that the full lab can survive a fire."

To survive the worst inferno that nature can throw at us, the Lab has deployed an intricately entwined array of defenses. Class A roofs, the most fire retardant roofing available, have been installed on all buildings. All buildings (except one metal-sided building) have fire sprinklers. Two water storage tanks have been added onsite with a third in the works, and water can be pumped by backup electrical generators even if the electrical and water supply to the Lab is shutoff. And, the Laboratory has its own onsite fire department.

Despite these measures, a firestorm would overrun the Laboratory, transforming it to smoky memory, were it not for an intensive, difficult, and unending vegetation modification effort. Guided by sophisticated computer models, this project shields the Lab against the next firestorm.

To recall the intensity of this threat, consider the observations of a San Francisco firefighter who helped stop the 1991 fire in a stand made behind the Claremont Hotel. "Rising and erratic fire-driven winds in excess of 65 mph preheated structures and foliage, and temperatures approached 2,000 degrees F. Large homes and large trees exploded in flame, and they would then generate firebrands (airborne embers) which were picked up by the fierce, hot winds -- which in turn ignited other structures and trees -- and soon they too would explode. In some places aluminum engine blocks and parts of burning automobiles melted and ran into the gutter."

With a wind-driven fire likely to attack the Lab from the wildlands to the east or northeast, vegetation management is the foundation of the Lab's defenses. Reducing fuel loads on an extensive, wooded site is a tough and tiresome undertaking, so daunting that many large institutional landowners in the East Bay Hills have barely begun such an effort. At the Lab, the fuel reduction effort was dramatically intensified six years ago, has been systematic and sustained, and is now within two years of completion. After that, vegetation management enters into a perpetual maintenance mode.

Many employees have contributed to the effort, all under the leadership of Deputy Laboratory Director Klaus Berkner. Among those who have been critical to its success are the aforementioned Don Bell; Tony Yuen, the Lab's fire marshall; Stacy Cox, our fire chief; and Bob Berninzoni who supervises the Lab landscaping staff and who has administered the contracts for tree cutting and the goat herds employed to graze and reduce fuel.

Projected flame height at Berkeley Lab in 1995 and 2000

Rich McClure is the Lab's point man for vegetation management. Any homeowner who has ever contemplated a serious effort to manicure their landscaping so as to mitigate the threat of fire has an inkling of the magnitude of the frustrating mission that he has undertaken. Perhaps it's McClure's temperament -- unassuming, patient, persistent, and resolute -- that has made him a model manager of the lab's sustained vegetation management effort. But that would overlook his expert knowledge of fire ecology.

A decade ago, says McClure, the effort to protect the Lab from fire relied on firebreaks at the perimeter of the lab. Since that time, computer modeling has shown that this defense would be a catastrophic failure.

"We modeled using the extreme 1991 firestorm conditions: vegetation is desiccated, high temperatures, strong winds, and low relative humidity. This," said McClure, "is the worst-case scenario. What we learned -- both from the 1991 fire and the modeling -- is that our existing perimeter firebreaks were not sufficient. The flame front from a firestorm coming at us from the east would be up to 60-feet-high and would generate enough heat and wind to overrun the site."

Even if firefighters had made a suicidal stand to stop this wall of flames, because of the level of fuel throughout the site, firebrands would have destroyed the lab.

"The Laboratory manages the entire site under the assumption that in a firestorm, thousands of firebrands will descend upon the Laboratory," says McClure. "These firebrands will ignite vegetation across the site and fire will consume the vegetation around individual buildings in less than ten minutes. But because of the vegetation management effort we have done, these fires will be low-temperature and low-flame. This is the keystone of our defenses: we have reduced fuel levels so that these fires cannot penetrate and ignite the buildings."

Throughout the landscape, the fire characteristics of the site have been evaluated. Where the risks are excessive, the Laboratory has modified native plant communities along the spectrum of the natural succession. The goal is to retard and to accelerate successional forces in selective areas so that fire risks are effectively managed using natural plant communities.

Six years into this complex effort, the Lab has expended a very modest $1.1 million with $600,000 of remaining corrective vegetative work to be done over the next two years. This represents about three-tenths of one percent of the value of just the Lab's buildings (not counting that which is inside). After this initial work is completed, the annual vegetation management bill to insure the future existence of the Lab will be approximately $100,000.

At the lab's flanks, additional firebreaks and enhancement of existing breaks have been engineered using computer models. Within these firebreaks and within selected wooded areas throughout the site, trees have been felled or thinned and had their lower limbs removed.

"You manage in a way to stop an incoming crown fire. You bring it down to the ground," said McClure. "Before, we would have had 60-foot flames burning uphill toward the Laboratory firehouse. Now, with the breaks and vegetation management, we would get three-to-five-foot flames."

Fifty acres of the Lab had been overgrown with French broom, a highly flammable exotic brush. Now, all of the French broom is gone. Every year, a crew comes in and removes any regrowth, a job that must be continued in perpetuity. But every year, the job becomes easier.

To sustain the fire-safe landscape that has been created by this project, the principles are relatively simple, said McClure. "Grasses we cut. Bushes or brush we thin. Trees we limb up. The end result is a wooded, park-like setting for a complex of buildings that is able to survive a wildland fire."

Computer modeling consistently indicated that the eucalyptus trees above Building 74 on the Lab's critical eastern flank would shower the Lab and Berkeley neighborhoods with firebrands. Now, said McClure, those trees are gone and there is not going to be a storm of firebrands streaming out of the Lab into neighboring residential areas.

Don Bell spelled out the benefit to the community: "Because the Lab is here, the neighboring community is safer for it. If a fire ignites to the east of the Lab under Diablo wind conditions, then that fire could travel through the Lab to burn into downtown Berkeley. Because of our fire management effort, the fire would not have fuel to continue. There is so little fuel here, the fire would be extinguished before reaching the city."

The Laboratory cannot escape its environment. Surrounded by the wildlands of Tilden Park, Strawberry and Claremont canyons, its spectacular hillside location is a mixed blessing. Thirteen times in the 20th century, Diablo winds ignited the East Bay Hills and one day, fire will ignite upwind of the Laboratory once again.

"We know there are going to be spot fires all over Lab," said McClure. "Even if we can't get them all out right away, if we sustain the ongoing effort, we should not lose any buildings. We should not suffer major damage."