Fire Risk Increased by Fuel, Terrain

It could be a cigarette, flicked carelessly out a car window. A blue spray of sparks kicked up by a low-leaning motorcycle on a sharp mountain curve. An arsonist, an illegal campfire, a dry lightning strike on a lazy fall day.

This much is certain: One day, a fire will start in the majestic, jungle-thick forest ringing Lake Arrowhead. And if conditions are right--if the day is hot, if the Santa Ana winds are blowing, if the brush has been baked dry by the sun--one of Southern California’s most beloved vacation spots will become a raging circle of fire.

“If a fire got going here ... it would be catastrophic,” said Bob Hertel, an architectural inspector at Lake Arrowhead. Then he corrected himself: “It’s not a matter of if,” he said, “but when.”

Ask any Southern California fire chief which places are at highest risk this summer, with conditions the driest on record, and he will answer that the risk is equally high wherever houses abut wild land. But some places, he might concede, are more equal than others. Dozens of communities in Southern California, Lake Arrowhead among them, have been built on a dare, in places where nature could readily reclaim them.

Firefighters weigh a range of factors--climate, topography, building styles, road width, fire history--as they consider which places are most vulnerable to, and least defensible from, fire.

Lake Arrowhead, where the forest has been allowed to grow unchecked since the area was clear-cut by loggers in the late 1800s, is near the top of many experts’ lists of at-risk places. There, nearly all the danger signals converge.

Also at high risk is Topanga Canyon, where the Santa Ana wind can blow like a bellows and roads dotted with wooden houses snake up brush-choked ravines. So are most of the “front range” communities along the San Bernardino and San Gabriel mountains--places such as Redlands and Upland, Sierra Madre and Tujunga.

In Ventura County, Fire Chief Bob Roper worries especially about portions of the Ojai Valley, Camarillo Heights, Conejo Valley, Wildwood Park, Ventu Park and some of the hilly places where Thousand Oaks spills into brushland.

Capt. Stephen Miller of the Orange County Fire Department declined to single out any communities, saying all are at risk. But a map of the county’s highest-risk areas shows hot spots abutting parts of Irvine, San Juan Capistrano and San Clemente.

Battalion Chief Mark Stormes of the Los Angeles Fire Department described his worst-case scenario: “A night-time, wind-driven, mountain-area fire. Everybody’s home. Everybody’s in bed.”

Where could that happen? He pointed to the map, vast swaths of which were colored red for danger.

“All of the canyons,” he said, “probably from the 405 to the Hollywood Freeway.”

Asst. Chief Herbert Spitzer of the L.A. County Fire Department has his own mental list of disasters waiting to happen: Glendale, Pasadena, Claremont, La Verne, Malibu and Pomona are among the names on it.

Spitzer also has this nightmarish vision: A fire breaks out along the Golden State Freeway frontage of Griffith Park in Los Angeles. It spreads unchecked through rugged canyons up and over the top of the park, driven by strong Santa Ana winds. The wind shoots showers of glowing embers onto tightly packed neighborhoods in Los Feliz, Silver Lake, Hollywood. A wild-land fire becomes an urban conflagration

“That,” said Spitzer, “wouldn’t be a very friendly fire at all.”

It would join a long list of unfriendly fires in California, from the 1906 San Francisco earthquake and fire to the 1993 blazes that swept through Southern California.

The worst was the Oakland Hills fire of October 1991. Ignited in brush, it blew through hillside neighborhoods that had long prided themselves on balancing urban life with nature. Within hours, 25 people were dead and nearly 3,000 homes had been destroyed.

The Oakland blaze prompted redrafting of building codes to make homes in fire-prone areas less likely to ignite. Along with the 1993 fires in Southern California, it also pushed people to reconsider their notions of beauty. Is manzanita beautiful or ominous when it nuzzles up to a wooden patio deck? What’s lovelier, an overhanging fir or a firebreak? And it prompted the state to undertake the massive task of classifying the places in California at highest risk of wildfire. Portions of more than 100 cities or counties in California were designated as Very High Fire Hazard Severity Zones, roughly two-thirds of them in the five-county Southern California region. These places are generally held to more stringent building and zoning standards by local officials.

Such zoning is not, however, a foolproof guide. The assessments were made in the mid-1990s and have not, in many cases, been updated. And many jurisdictions were exempted because they already had tough fire-safety guidelines.

“As a result, true hazards throughout the state were not necessarily identified,” according to the state’s Field Hazard Zoning Field Guide, published in 2000.

Firefighters, for the most part, know where the hazards are. As human encroachment into wilderness has grown, so has fire science.

They know, for instance, that steep slopes burn faster than flat places. That south-facing slopes, which receive more sun, are more likely to burn than north ones. That a place that hasn’t burned for many years will have more fuel and be harder to control than a place that has burned recently.

They know which kinds of buildings survive best, and how wide a road needs to be to allow fire engines in while residents head out. That tree limbs drooping near the ground can catch fire and spread it to the crown, where the flames can jump from treetop to treetop--the hardest kind of fire to fight.

One gauge of danger is the burn index, a measurement of the relative difficulty of fire control. In a winter rainstorm, the burn index would be zero. The highest it can go is 350, a largely hypothetical peak that might be reached on a broiling fall day when humidity is near zero and strong winds are buffeting a steep south-facing slope of extremely dry brush.

“When the Old Topanga fire burned [in 1993], it was running in the 170 to 190 range in the Santa Monica Mountains,” said Spitzer, the county fire official. “Any time you get up there to those kinds of numbers--160, 170--those fires are going to be very difficult to control.”

Several weeks ago, Spitzer noted that the fire index in the Santa Clarita area of northern Los Angeles County was 191. Shortly after that, firefighters struggled to control blazes on two consecutive days there. The fires charred 400 acres and damaged one home.

A key component of the burn index is what firefighters call “live fuel moisture,” a way of expressing a plant’s water content. When the water in a plant weighs 60% as much as its dry material, live brush burns as if it were dead. Much lower, and the plants die.

In Los Angeles County, where last winter’s rainfall was the lowest on record, the live fuel moisture at the end of June averaged 72%. By mid-July, it was just above 60%--normal for the beginning of November, when plants typically are at their driest, but unheard of for the middle of summer.

“We’re into new ground. We’ve never been here before,” Spitzer said.

Not all disastrous fire seasons have followed extremely dry winters. Some of the worst--1978 and 1993--followed wet winters, when rainfall nurtured plants that were then dried by the summer heat.

What worries fire officials this year is not an overgrowth of brush from last winter but the trees and brush that have grown over many years, protected by vigilant firefighting policies.

You can see this growth by the truckload any day at the Heaps Peak dump near Lake Arrowhead, to which anxious homeowners are carting mountains of brush and tree limbs, some of it built up over decades.

Richard Minnich, a professor of earth science at UC Riverside, has spent years studying the forests and brush lands of Southern California and northern Baja California. At the moment, he said, the Lake Arrowhead-Crestline area has the densest forest in the region. It’s two to three times as thick as similar terrain in Baja, where Mexican officials have allowed fires to burn periodically over the years.

When fires burn in Mexican forests, he said, they have a rejuvenating effect, clearing out deadwood and leaving the strongest trees alive. That wouldn’t happen today around Lake Arrowhead, he said. Not only are forests dangerously dense, many trees are dead or dying from a bark beetle infestation.

Most homes are built of wood, many with wooden roofs. Given the right conditions, a fire could incinerate everything in its path. “You could change the whole ecosystem in one event,” Minnich said.

His is not exactly a voice in the wilderness--not anymore. His warning is echoed by Donna Newlin, a resident of the Smiley Park area just southeast of Lake Arrowhead, parts of which burned in 1997.

“A fire that would burn in here,” she said, “would be so intense that you couldn’t even get close.”

Newlin, a member of the ski patrol at a nearby resort, scrambled down the slope behind her home, an airy, alpine-styled place with a big wooden deck. She and her husband, a Redlands firefighter, have done what they could to protect themselves. Their roof is made of fire-resistant composite materials. They have cleared brush and trimmed trees in a wide ring around the house. They keep their garden well watered.

But Newlin recognizes certain realities. The house faces south and stares into a ravine--known in fire science as a “chimney.” The road leading to their home is narrow and winding--a dubious reach for a fire engine. And beyond their land is an area that hasn’t burned for the better part of a century.

Newlin is active in the Mountain Rim Fire Safe Council, which works to raise awareness of fire danger, and has helped get grants to clear brush around Smiley Park. Near her home is one such area that was cleared: The forest floor is sun-dappled for the first time in years, and so many broomstick-sized trees have been removed that Newlin’s husband was able to build a Frisbee golf course.

A fire that started there might be relatively easy to put out. Not so behind the Newlin residence.

“Why do we live here?” she said. “It’s beautiful, it’s quiet, we have a lot of space. The kids can ride their bikes all over the neighborhood without being afraid of getting hit by a car.”

A homeowner can do only so much to protect herself. Ultimately, vast tracts of forest will have to be thinned before this place can be anything close to safe.

Fire officials speak of creating “defensible space” to retard the growth of fires. They also talk of fires “coming into alignment,” meaning conditions are ripe for a fire to spread. Minnich considered what might happen if the forces align this summer, if a fire breaks out in Southern California in the wrong place at the wrong time.

“It’s an indefensible situation,” he said.