For five consecutive nights, I stood at my front door and watched the Station fire lick at the hillside. The tongues of shooting flame looked to be only a few hundred feet away. Actually, the fire was burning a mile and a half up the mountain from my home in La Crescenta.
I live below Foothill Boulevard, I comforted myself. There was no way the fire was going to make it down here. We aren’t like those crazy people who tempt fate by living in harm’s way. Even after a 2 a.m. evacuation call, I believed my family and I were safe.
And we were.
During the fire, my brother, Frank, who lives in Tahiti and studies how geologic factors affect landscapes, looked at my house and the fire on Google Earth. He told me to get John McPhee’s 1989 book, “The Control of Nature.”
“There’s a great chapter on what happens next,” he said.
What happens next? They put out the fire, the smoke clears and life goes on. The hillsides will need watching for mudslides, as always after a fire.
Two days later, a journalist friend specializing in climate issues mentioned the same book. “Read the Los Angeles chapter and then act accordingly,” he said, raising his eyebrows ominously.
Before the fire, I hiked regularly up Pine Cone Road with a 25-pound pack, training for a Mt. Whitney ascent. The road is not far from my home. Lined with suburban houses, it rises at a 41% incline and snakes high into the chaparral-laden mountains, making it the perfect training ground when there isn’t time to make it to the “real” mountains. At the top of Pine Cone, a concrete-lined reservoir marks the end of the trail: Shields Upper Debris Basin.
As it turns out, McPhee’s chapter, “Los Angeles Against the Mountains,” begins on Pine Cone Road with the story of the Genofile home. On a rainy February night in 1978, three years after wildfires in the area, Jackie Genofile and her children looked up Pine Cone Road from a bedroom window. What they saw would terrify anyone: “a massive blackness, moving. It was not a landslide, not a mudslide, not a rock avalanche; nor by any means was it the front of a conventional flood.”
It was a debris flow; water mixed with solid material. Rock porridge, McPhee calls it.
“The dark material coming toward the Genofiles was not only full of boulders; it was so full of automobiles it was like bread dough mixed with raisins. On its way down Pine Cone Road, it plucked cars from driveways in the street. When it crashed into the Genofiles’ house, the shattering of safety glass made terrific explosive sounds
McPhee describes a nightmare. Debris spilled through the house, trapped the Genofiles, flowed over the roof. The house filled in six minutes. “The mud stopped rising near the children’s chins.”
Shields Upper Debris Basin, designed to catch 50,000 tons, had overflowed its capacity. “The Genofiles’ house was buried to the eves. Boulders sat on the roof. Thirteen automobiles were packed around the building, including five in the pool.”
But such freak disasters can happen to anyone, anywhere, right?
Not exactly, as McPhee patiently explains. The San Gabriels -- “in their tectonic youth,” his book tells me -- are rising and disintegrating at a rate that is among the fastest in the world. Their steep canyons are covered in chaparral, one of the most combustible of plant materials, ensuring that when a fire comes, it will raze everything in its reach. Add to that the fact that burned chaparral releases resins that coat the soil, making it pretty much waterproof, and that some of the most concentrated rainfall in the United States occurs in the San Gabriel Mountains.
Typically, exceptional debris flows occur when at least five rainy days have put seven inches of water on the ground and are followed immediately with even heavier rainfall. “On that day,” McPhee writes, “the debris mobilizes.” In 1978, just before the Genofiles’ house filled with debris, nearly an inch and a half of rain fell in 25 minutes.
At least I know what to watch for.
I hold McPhee’s book in my hands, and I wonder what to do with this information. Should I warn my neighbors? Check the insurance policy for “debris flow”? Tell people at the grocery store checkout stand to read the chapter on Los Angeles and act accordingly?
And yet, there’s no guarantee that a monster debris flow will occur this winter, even if wet weather arrives with the El Nino predicted by the National Oceanic and Atmospheric Administration. But if not this winter ...
Exceptional debris flows occur at least once a decade. Frequent, but not frequent enough to deter people from living in endangered areas. Communities such as Sunland/Tujunga, La Crescenta, La Canada Flintridge, Altadena, Sierra Madre and others abutting the San Gabriels are beautiful, with mountain views to one side and city views to the other. The air is a bit cooler and cleaner. There’s a reason people like to live here. There’s a reason we live here.
But now I can’t help but wonder if McPhee’s story will worm its way into me, eventually forcing a move. Or will I become one of the crazy people who knows the risks and chooses to live here anyway?
Denial doesn’t break down as easily as the mountains. But it’s beginning to crumble. For now, I’m still trying to find solace in the fact I live below Foothill Boulevard -- as if debris is aware of that marker. The flow that almost killed the Genofiles didn’t get near my neighborhood. But even that thin comfort can be stripped away. In 1934, I read, a debris flow brought a boulder eight feet in diameter into Montrose, about half a mile farther down the mountain from me.