debris flow

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Montecito is now a quarry with houses in it:

So far twenty dead have been removed. It will take much more time to remove twenty thousand dump truck loads of what geologists call “debris,” just to get down to where civic infrastructure (roads, water, electric, gas) can be fixed. It’s a huge thing.

The big questions:

  1. Did we know a catastrophe this huge was going to happen? (And if so, which among us were the “we” who knew?)
  2. Was there any way to prevent it?

Geologists had their expectations, expressed as degrees of likelihood and detailed on this map by the United States Geological Survey:

That was dated more than a month before huge rains revised to blood-red the colors in the mountains above town. Worries of County Supervisors and other officials were expressed in The Independent on January 3rd and 5th. Edhat also issued warnings on January 5th and 6th.

Edhat’s first report began, “Yesterday, the National Weather Service issued a weather briefing of a potential significant winter storm for Santa Barbara County on January 9-10. With the burn scar created by the Thomas Fire, the threat of flash floods and debris/mud flows is now 10 times greater than before the fire.”

But among those at risk, who knew what a “debris/mud flow” was—especially when nobody had ever seen one of those anywhere around here, even after prior fires?

The first Independent story (on January 3rd) reported, “County water expert Tom Fayram said county workers began clearing the debris basins at San Ysidro and Gobernador canyons ‘as soon as the fire department would let us in.’ It is worth noting, Lewin said, that the Coast Village Road area flooded following the 1971 Romero Fire and the 1964 Coyote Fire. While touring the impact areas in recent days, (Office of Emergency Management Director Robert) Lewin said problems have already occurred. ‘We’re starting to see gravity rock fall, he said. ‘One rock could close a road.'”

The best report I’ve seen about what geologists knew, and expected, is The Independent‘s After the Mudslides, What Does the Next Rain Hold for Montecito?, published four days after the disaster. In that report, Kevin Cooper of the U.S. Forest Service said, “no one alive has probably ever seen one before.” [January 18 update: Nick Welch in The Independent reports, “Last week’s debris flow was hardly Santa Barbara’s first. Jim Stubchaer, then an engineer with County Flood Control, remembers the avalanche of mud that took 250 homes back in November 1964 when heavy rains followed quickly on the heels of the Coyote Fire. He was there in 1969 and 1971 when it happened again.” Here is a long 2009 report on the Coyote Fire in The Independent by Ray Ford, now with Noozhawk. No mention of the homes lost in there. Perhaps Ray can weigh in.]

My point is that debris flows over Montecito ae a sure bet in geologic time, but not in the human one. In the whole history of Montecito and Santa Barbara (of which Montecito is an unincorporated part), there are no recorded debris flows that started on mountain slopes and spread all the way to the sea. But on January 9th we had several debris flows on that scale, originating simultaneously in the canyons feeding Montecito, San Ysidro and Romero Creeks. Those creeks are dry most of the time, and beautiful areas in which to build homes: so beautiful, in fact, that Montecito is the other Beverly Hills. (That’s why all these famous people have called it home.)

One well-studied prehistoric debris flow in Santa Barbara emptied a natural lake that is now Skofield Park,dumping long-gone mud and lots of rocks in Rattlesnake Canyon, leaving its clearest evidence in a charming tree-shaded boulder field next to Mission Creek called Rocky Nook Park.

What geologists at UCSB learned from that flow is detailed in a 2001 report titled UCSB Scientists Study Ancient Debris Flows. It begins, “The next ‘big one’ in Santa Barbara may not be an earthquake but a boulder-carrying flood.” It also says that flood would “most likely occur every few thousand years.”

And we got one in Montecito last Tuesday.

I’ve read somewhere that studies of charcoal from campfires buried in Rocky Nook Park date that debris flow at around 500 years ago. This is a good example of how the geologic present fails to include present human memory. Still, you can get an idea of how big this flow was. Stand in Rattlesnake Canyon downstream from Skofield Park and look at the steep rocky slopes below houses on the south side of the canyon. It isn’t hard to imagine the violence that tore out the smooth hillside that had been there before.

To help a bit more with that exercise, here is a Google Streetview of Scofield Park, looking down at Santa Barbara through Rattlesnake Canyon:

I added the red line to show the approximate height of the natural dam that broke and released that debris flow.

I’ve also learned that the loaf-shaped Riviera landform in Santa Barbara is not a hunk of solid rock, but rather what remains of a giant landslide that slid off the south face of the Santa Ynez Mountains and became free-standing after creeks eroded out the valley behind. I’ve also read that Mission Creek flows westward around the Riviera and behind the Mission because the Riviera itself is also sliding the same direction on its own tectonic sled.

We only see these sleds moving, however, when geologic and human time converge. That happened last Tuesday when rains Kevin Cooper calls “biblical” hit in the darkest hours, saturating the mountain face creek beds that were burned by the Thomas Fire just last month. As a result, debris flows gooped down the canyons and stream valleys below, across Montecito to the sea, depositing lots of geology on top of what was already there.

So in retrospect, those slopes in various colors in the top map above should have been dark red instead. But, to be fair, much of what geology knows is learned the hard way.

Our home, one zip code west of Montecito, is fine. But we can’t count how many people we know who are affected directly. One friend barely escaped. Some victims were friends of friends. Some of the stories are beyond awful.

We all process tragedies like this in the ways we know best, and mine is by reporting on stuff, hopefully in ways others are not, or at least not yet. So I’ll start with this map showing damaged and destroyed buildings along the creeks:

At this writing the map is 70% complete. [January 17 update: 95%.] I’ve clicked on all the red dots (which mark destroyed buildings, most of which are homes), and I’ve copied and pasted the addresses that pop up into the following outline, adding a few links.

Going downstream along Cold Spring Creek, Hot Springs Creek and Montecito Creek (which the others feed), gone are—
  1. 817 Ashley Road
  2. 817 Ashley Road (out building)
  3. 797 Ashley Road
  4. 780 Ashley Road. Amazing architectural treasure that last sold for $12.9 million in ’13.
  5. 809 Ashley Road
  6. 809 Ashley Road (there are two at one address)
  7. 747 Indian Lane
  8. 631 Parra Grande Lane. That’s the mansion where the final scene in Scarface was shot.
  9. 590 Meadowood Lane
  10. 830 Rockbridge Road
  11. 800 Rockbridge Road
  12. 790 Rockbridge Road
  13. 787 Riven Rock Road B
  14. 1261 East Valley Road
  15. 1240 East Valley Road A (mansion)
  16. 1240 East Valley Road B (out building)
  17. 1254 East Valley Drive
  18. 1255 East Valley Road
  19. 1247 East Valley Road A
  20. 1247 East Valley Road B (attached)
  21. 1231 East Valley Road A
  22. 1231 East Valley Road B (detached)
  23. 1231 East Valley Road C (detached)
  24. 1221 East Valley Road A
  25. 1221 East Valley Road B
  26. 369 Hot Springs Road
  27. 341 Hot Springs Road A
  28. 341 Hot Springs Road B
  29. 341 Hot Springs Road C
  30. 355 Hot Springs Road
  31. 335 Hot Springs Road A
  32. 335 Hot Springs Road B
  33. 333 Hot Springs Road (Not marked in final map)
  34. 341 Hot Springs Road A
  35. 341 Hot Springs Road B
  36. 341 Hot Springs Road C
  37. 340 Hot Springs Road
  38. 319 Hot Springs Road
  39. 325 Olive Mill Road
  40. 285 Olive Mill Road
  41. 275 Olive Mill Road
  42. 325 Olive Mill Road
  43. 220 Olive Mill Road
  44. 200 Olive Mill Road
  45. 275 Olive Mill Road
  46. 180 Olive Mill Road
  47. 170 Olive Mill Road
  48. 144 Olive Mill Road
  49. 137 Olive Mill Road
  50. 139 Olive Mill Road
  51. 127 Olive Mill Road
  52. 196 Santa Elena Lane
  53. 192 Santa Elena Lane
  54. 179 Santa Isabel Lane
  55. 175 Santa Elena Lane
  56. 142 Santo Tomas Lane
  57. 82 Olive Mill Road
  58. 1308 Danielson Road
  59. 81 Depot Road
  60. 75 Depot Road
Along Oak Creek—
  1. 601 San Ysidro Road
  2. 560 San Ysidro Road B
Along San Ysidro Creek—
  1. 953 West Park Lane
  2. 941 West Park Lane
  3. 931 West park Lane
  4. 925 West park Lane
  5. 903 West park Lane
  6. 893 West park Lane
  7. 805 W Park Lane
  8. 881 West park Lane
  9. 881 West park Lane (separate building, same address)
  10. 1689 Mountain Drive
  11. 900 San Ysidro Lane C (all the Lane addresses appear to be in San Ysidro Ranch)
  12. 900 San Ysidro Lane Cottage B
  13. 900 San Ysidro Lane Cottage A
  14. 900 San Ysidro Lane Cottage D
  15. 900 San Ysidro Lane E
  16. 900 San Ysidro Lane F
  17. 900 San Ysidro Lane G
  18. 900 San Ysidro Lane H
  19. 900 San Ysidro Lane I
  20. 900 San Ysidro Lane J
  21. 900 San Ysidro Lane K
  22. 900 San Ysidro Lane L
  23. 900 San Ysidro Lane M
  24. 900 San Ysidro Lane N
  25. 900 San Ysidro Lane O
  26. 900 San Ysidro Lane R
  27. 900 San Ysidro Lane S
  28. 900 San Ysidro Lane T
  29. 888 San Ysidro Lane A
  30. 888 San Ysidro Lane B
  31. 888 San Ysidro Lane C
  32. 888 San Ysidro Lane D
  33. 888 San Ysidro Lane E
  34. 888 San Ysidro Lane F
  35. 805 West Park Lane B
  36. 799 East Mountain Drive
  37. 1801 East Mountain Lane
  38. 1807 East Mountain Drive
  39. 771 Via Manana Road
  40. 899 El Bosque Road
  41. 771 Via Manana Road
  42. 898 El Bosque Road
  43. 800 El Bosque Road A (Casa de Maria)
  44. 800 El Bosque Road B (Casa de Maria)
  45. 800 El Bosque Road C (Casa de Maria)
  46. 559 El Bosque Road (This is between Oak Creek and San Ysidro Creek)
  47. 680 Randall Road
  48. 670 Randall Road
  49. 660 Randall Road
  50. 650 Randall Road
  51. 640 Randall Road
  52. 630 Randall Road
  53. 619 Randall Road
  54. 1685 East Valley Road A
  55. 1685 East Valley Road B
  56. 1685 East Valley Road C
  57. 1696 East Valley Road
  58. 1760 Valley Road A
  59. 1725 Valley Road A
  60. 1705 Glenn Oaks Drive A
  61. 1705 Glen Oaks Drive B
  62. 1710 Glen Oaks Drive A
  63. 1790 Glen Oaks Drive A
  64. 1701 Glen Oaks Drive A
  65. 1705 Glen Oaks Drive A
  66. 1705 East Valley Road A
  67. 1705 East Valley Road B
  68. 1705 East Valley Road C
  69. 1780 Glen Oaks Drive N/A
  70. 1780 Glen Oaks Drive (one on top of the other)
  71. 1774 Glen Oaks Drive
  72. 1707 East Valley Road A
  73. 1685 East Valley Road C
  74. 1709 East Valley Road
  75. 1709 East Valley Road B
  76. 1775 Glen Oaks Drive A
  77. 1775 Glen Oaks Drive B
  78. 1779 Glen Oaks Drive A
  79. 1779 Glen Oaks Drive B
  80. 1779 Glen Oaks Drive C
  81. 1781 Glen Oaks Drive A
  82. 1711 East Valley Road (This and what follow are adjacent to Oprah)
  83. 1715 East Valley Road A
  84. 1715 East Valley Road B
  85. 1719 East Valley Road
  86. 1721 East Valley Road A (This might survive. See Dan Seibert’s comment below)
  87. 1721 East Valley Road B (This might survive. See Dan Seibert’s comment below)
  88. 1721 East Valley Road C (This might survive. See Dan Seibert’s comment below)
  89. 1694 San Leandro Lane A
  90. 1694 San Leandro Lane D
  91. 1690 San Leandro Lane C
  92. 1690 San Leandro Lane A
  93. 1694 San Leandro Lane B
  94. 1696 San Leandro Lane
  95. 1710 San Leandro Lane A
  96. 1710 San Leandro Lane B
  97. 190 Tiburon Bay Lane
  98. 193 Tiburon Bay Lane A
  99. 193 Tiburon Bay Lane B
  100. 193 Tiburon Bay Lane C
  101. 197 Tiburon Bay Lane A
Along Buena Vista Creek—
  1. 923 Buena Vista Avenue
  2. 1984 Tollis Avenue A
  3. 1984 Tollis Avenue B
  4. 1984 Tollis Avenue C
  5. 670 Lilac Drive
  6. 658 Lilac Drive
  7. 2075 Alisos Drive (marked earlier, but I don’t see it in the final map)
  8. 627 Oak Grove Lane
Along Romero Creek—
  1. 1000 Romero Canyon Road
  2. 1050 Romero Canyon Road
  3. 860 Romero Canyon Road
  4. 768 Winding Creek Lane
  5. 745 Winding Creek Lane
  6. 744 Winding Creek Lane
  7. 2281 Featherhill Avenue B

Below Toro Canyon—

  1. 876 Toro Canyon Road
  2. 572 Toro Canyon Park Road

Along Arroyo Paredon, between Summerland and Carpinteria, not far east of the Toro Canyon—

  1. 2000 Cravens Lane

Ten flanking Highway 101 by the ocean are marked as damaged, including four on Padero Lane.

When I add those up, I get 142 163* 178† among the destroyed alone.

[* This is on January 17, when the map says it is 95% complete. All the additions appear to be along San Ysidro Creek, especially on San Ysidro Lane, which I believe is mostly in San Ysidro Ranch. Apparently nearly the whole place has been destroyed. Adjectives such as “lovely” fail to describe what it was.]

[† This is on January 18, when the map is complete. I’ll need to go over it again, because there are subtractions as well as additions. Additional note: on March 22, the resident at 809 Ashley Road asked me to make sure that address was also added. There are two homes at that address, both gone.]

Now let’s go back and look more closely at this again from the geological perspective.

What we see is a town revised by nature in full disregard for what was there before—and in full obedience to the pattern of alluvial deposition on the flanks of all fresh mountains that erode down almost as fast as they go up.

This same pattern accounts for much of California, including all of the South Coast and the Los Angeles basin.

To see what I mean, hover your mind above Atlanta and look north at the southern Appalachians. Then dial history back five million years. What you see won’t look much different. Do the same above Los Angeles or San Francisco and nothing will be the same, or even close. Or even there at all.

Five million years is about 1/1000th of Earth’s history. If that history were compressed to a day, California showed up in less than the last forty seconds. In that short time California has formed and re-formed constantly, and is among the most provisional landscapes in the world. All of it is coming up, sliding down, spreading out and rearranging itself, and will continue doing so through all the future that’s worth bothering to foresee. Debris flows are among nature’s most casual methods for revising landscapes. (By the way, I am writing this in a San Marino house that sits atop the Raymond Fault scarp, which on the surface takes the form of a forty-foot hill. The stack of rock strata under the bottom of that hill is displaced 17,000 feet from the identical suite under the base at the top. Many earthquakes produced that displacement, while erosion has buffed 16,960 feet of rock and soil off the top.)

So we might start to look at the Santa Ynez Mountains behind Santa Barbara and Montecito not as a stable land form but rather as a volcano of mud and rock that’s sure to go off every few dozen or hundreds of years—and will possibly deliver a repeat performance if we get more heavy rains and there is plenty of debris left to flow out of mountain areas adjacent to those that flowed on January 9th. If there’s a lot of it, why even bother saving Montecito?

Here’s why:

One enters the Engineering building at the University of Wyoming under that stone plaque, which celebrates what may be our species’ greatest achievement and conceit: controlling nature. (It’s also why geology is starting to call our present epoch the anthropocene.)

This also forecasts exactly what we will do for Montecito. In the long run we’ll lose to nature. But meanwhile we strive on.

In our new strivings, it will help to look toward other places in California that are more experienced with debris flows, because they happen almost constantly there. The largest of these by far is Los Angeles, which has placed catch basins at the mouths of all the large canyons coming out of the San Gabriel Mountains. Most of these dwarf the ones above Montecito. All resemble empty reservoirs. Some are actually quarries for rocks and gravel that roll in constantly from the eroding creek beds above. None are pretty.

To understand the challenge involved, it helps to read John McPhee’s classic book The Control of Nature, which takes its title from the inscription above. Fortunately, you can start right now by reading the first essay in a pair that became the relevant chapter of that book. It’s free on the Web and called Los Angeles Against the Mountains I. Here’s an excerpt:

Debris flows amass in stream valleys and more or less resemble fresh concrete. They consist of water mixed with a good deal of solid material, most of which is above sand size. Some of it is Chevrolet size. Boulders bigger than cars ride long distances in debris flows. Boulders grouped like fish eggs pour downhill in debris flows. 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.

The Genofiles were a family that barely survived a debris flow on a slope of Verdugo Mountain, overlooking Los Angeles from Glendale. Here’s another story, about another site not far away:

The snout of the debris flow was twenty feet high, tapering behind. Debris flows sometimes ooze along, and sometimes move as fast as the fastest river rapids. The huge dark snout was moving nearly five hundred feet a minute and the rest of the flow behind was coming twice as fast, making roll waves as it piled forward against itself—this great slug, as geologists would describe it, this discrete slug, this heaving violence of wet cement. Already included in the debris were propane tanks, outbuildings, picnic tables, canyon live oaks, alders, sycamores, cottonwoods, a Lincoln Continental, an Oldsmobile, and countless boulders five feet thick. All this was spread wide a couple of hundred feet, and as the debris flow went through Hidden Springs it tore out more trees, picked up house trailers and more cars and more boulders, and knocked Gabe Hinterberg’s lodge completely off its foundation. Mary and Cal Drake were standing in their living room when a wall came off. “We got outside somehow,” he said later. “I just got away. She was trying to follow me. Evidently, her feet slipped out from under her. She slid right down into the main channel.” The family next door were picked up and pushed against their own ceiling. Two were carried away. Whole houses were torn loose with people inside them. A house was ripped in half. A bridge was obliterated. A large part of town was carried a mile downstream and buried in the reservoir behind Big Tujunga Dam. Thirteen people were part of the debris. Most of the bodies were never found.

This is close to exactly what happened to Montecito in the wee hours of January 9th. (As of March 22, two of the 23 dead still haven’t been recovered, and probably never will be.) (In September 2018 a first responder I talked with said the bodies of a least one the two missing victims, a teenage boy and a toddler, were probably carried to the ocean.)

As of now the 8000-plus residents of Montecito are evacuated and forbidden to return for at least another two weeks—and maybe much longer if officials declare the hills above town ready to flow again.

Highway 101—one of just two major freeways between Southern and Northern California, is closed indefinitely, because it is now itself a stream bed, and re-landscaping the area around it, to get water going where it should, will take some time. So will fixing the road, and perhaps bridges as well.

Meanwhile getting in and out of Santa Barbara from east of Montecito by car requires a detour akin to driving from Manhattan to Queens by way of Vermont. And there have already been accidents, I’ve heard, on highway 166, which is the main detour road. We’ll be taking that detour or one like it on Thursday when we head home via Los Angeles after we fly there from New York, where I’m packing up now.

Expect this post to grow and change.

Bonus links:

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Anybody who refuses to leave a mudslide evacuation area needs to watch this video:

It’s a live recording of the slide that killed ten people in LaConchita, California, on January 10, 2005. We know people who knew people who were killed in that slide. The story of the Wallet family is especially tragic. Jimmy Wallet was walking back from a corner store with some ice cream for his family when the mudslide in the video above destroyed his house before his eyes, burying his wife and three little daughters. Only he and his teenage daughter, who was out with friends, lived. Six others also died.

And this wasn’t  an especially big slide — or the first to strike that little community. Here’s one from five years earlier. That killed people too.

I’ve been listening to KNX, which has been reporting on the heavy weather in Southern California, and I’m amazed to hear that a large percentage (40%, I think the reporter said) of evacuees are waiting it out.

Here’s the deal, folks: mudslides are inevitable. If you live below a steep hill or mountain slope in a part of Southern California that’s getting heavy rain, and you’re under an evacuation order, get out. Right now (5:45pm Pacific), Acton. La Crescenta, La Cañada-Flintridge, Glendale, Tujunga Foothill and Sierra Madre all have a total of nearly 2000 homes under evacuation order. (So says the official speaking at a news conference on KNX right now.)

Yesterday I shared some of what John McPhee wrote in The Control of Nature about a mudslide (in Glendale — in the same area under evacuation orders now. Here is the whole passage, courtesy of  this page on Los Angeles provided by United States Geological Survey:

In Los Angeles versus the San Gabriel Mountains, it is not always clear which side is losing. For example, the Genofiles, Bob and Jackie, can claim to have lost and won. They live on an acre of ground so high that they look across their pool and past the trunks of big pines at an aerial view over Glendale and across Los Angeles to the Pacific bays. The setting, in cool dry air, is serene and Mediterranean. It has not been everlastingly serene.

On a February night some years ago, the Genofiles were awakened by a crash of thunder — lightning striking the mountain front. Ordinarily, in their quiet neighborhood, only the creek beside them was likely to make much sound, dropping steeply out of Shields Canyon on its way to the Los Angeles River. The creek, like every component of all the river systems across the city from mountains to ocean, had not been left to nature. Its banks were concrete. Its bed was concrete. When boulders were running there, they sounded like a rolling freight. On a night like this, the boulders should have been running. The creek should have been a torrent. its unnatural sound was unnaturally absent. There was, and had been, a lot of rain.

The Genofiles had two teen-age children, whose rooms were on the uphill side of the one-story house. The window in Scott’s room looked straight up Pine Cone Road, a cul-de-sac, which, with hundreds like it, defined the northern limit of the city, the confrontation of the urban and the wild. Los Angeles is overmatched on one side by the Pacific Ocean and on the other by very high mountains. With respect to these principal boundaries, Los Angeles is done sprawling. The San Gabriels, in their state of tectonic youth, are rising as rapidly as any range on Earth. Their loose inimical slopes flout the tolerance of the angle of repose. Rising straight up out of the megalopolis, they stand ten thousand feet above the nearby sea, and they are not kidding with this city. Shedding, spalling, self-destructing, they are disintegrating at a rate that is also among the fastest in the world. The phalanxed communities of Los Angeles have pushed themselves hard against these mountains, an aggression that requires a deep defense budget to contend with the results. Kimberlee Genofile called to her mother, who joined her in Scott’s room as they looked up the street. From its high turnaround, Pine Cone Road plunges downhill like a ski run, bending left and then right and then left and then right in steep christiania turns for half a mile above a three-hundred-foot straight-away that aims directly at the Genofiles’ house. Not far below the turnaround, Shields Creek passes under the street, and there a kink in its concrete profile had been plugged by a six-foot boulder. Hence the silence of the creek. The water was not spreading over the street. It descended in heavy sheets. As the young Genofiles and their mother glimpsed it in the all but total darkness, the scene was suddenly illuminated by a blue electrical flash. In the blue light they saw 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. In Jackie’s words, “It was just one big black thing coming at us, rolling, rolling with a lot of water in front of it, pushing the water, this big black thing. It was just one big black hill coming toward us.”

In geology, it would be known as a debris flow. Debris flows amass in stream valleys and more or less resemble fresh concrete. They consist of water mixed with a good deal of solid material, most of which is above sand size. Some of it is Chevrolet size. Boulders bigger than cars ride long distances in debris flows. Boulders grouped like fish eggs pour downhill in debris flows. 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 up cars from driveways and the street. When it crashed into the Genofiles’ house, the shattering of safety glass made terrific explosive sounds. A door burst open. Mud and boulders poured into the hall. We’re going to go, Jackie thought. Oh, my God, what a hell of a way for the four of us to die together.

The parents’ bedroom was on the far side of the house. Bob Genofile was in there kicking through white satin draperies at the paneled glass, smashing it to provide an outlet for water, when the three others ran in to join him. The walls of the house neither moved nor shook. As a general contractor, Bob had built dams, department stores, hospitals, six schools, seven churches, and this house. It was made of concrete block with steel reinforcement, 16 inches on center. His wife had said it was stronger than any dam in California. His crew had called it “the fort.” In those days, 20 years before, the Genofiles’ acre was close by the edge of the mountain brush, but a developer had come along since then and knocked down thousands of trees and put Pine Cone Road up the slope. Now Bob Genofile was thinking, I hope the roof holds. I hope the roof is strong enough to hold. Debris was flowing over it. He told Scott to shut the bedroom door. No sooner was the door closed that it was battered down and fell into the room. Mud, rock, water poured in. It pushed everybody against the far wall. “Jump on the bed,” Bob said. The bed began to rise. Kneeling on it — on a gold velvet spread — they could soon press their palms against the ceiling. The bed also moved toward the glass wall. The two teen-agers got off, to try to control the motion, and were pinned between the bed’s brass railing and the wall. Boulders went up against the railing, pressed it into their legs, and held them fast. Bob dived into the muck to try to move the boulders, but he failed. The debris flow, entering through windows as well as doors, continued to rise. Escape was still possible for the parents but not for the children. The parents looked at each other and did not stir. Each reached for and held one of the children. Their mother felt suddenly resigned, sure that her son and daughter would die and she and her husband would quickly follow. The house became buried to the eaves. Boulders sat on the roof. Thirteen automobiles were packed around the building, including five in the pool. A din of rocks kept banging against them. The stuck horn of a buried car was blaring. The family in the darkness in their fixed tableau watched one another by the light of a directional signal, endlessly blinking. The house had filled up in six minutes, and the mud stopped rising near the children’s chins.”

Note that these flows don’t happen only when it’s still raining. Here’s one that happened along the Hayward Fault, in Fremont, that I remember watching from across the South Bay when we lived in Emerald Hills, California, in the late Nineties. It moved slowly and didn’t take out any houses; but it almost did, and was dramatic to watch. It wasn’t raining at the time. The mountainside was saturated with water from earlier rains, and chose its own time to give.

In terms of Geology, California is new. If you were to run a short video of the last few hundred thousand years in Southern California, you’d see a riot of mountains forming, sliding sideways and collapsing. If you were to do the same for the mountains of Arkansas or North Carolina, you’d see almost nothing happening.

Living anywhere is a game of russian roulette with nature: a bet that grand geologic or weather events will not occur within our brief lifespans. In communities like La Conchita, and others placed below dirt sure to move, there are many more bullets in the chambers.

But denial is a powerful force. When I first moved to Santa Barbara, and drove past La Conchita on Highway 1, I was astounded that anybody would chance to build there, because big landslides had obviously happened already, and more were sure to come. Since the mudslide of 2005, many people continue to live in La Conchita, and insist that the county “fix” the mountain above them — even though geologists have studied the region closely and said this:

The 1995 and 2005 landslides in the 200-m high sea cliff above the community of La Conchita, California, are known to be part of a reactivated Holocene prehistoric landslide. We propose that the prehistoric Holocene slide is part of a much larger, several hundred million cubic meter late Pleistocene slide complex composed of upper slumps and lower flows, informally termed as the Rincon Mountain megaslide.

On the positive side, rain on SoCal’s low elevations in winter means snow on the high peaks. If the air clears, Los Angeles will be flanked by white alps. I guarantee great skiing on Mt. Baldy when this thing is over. Provided there isn’t a debris flow blocking the road going up there.

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