Assault on Devil's Slide: A 150-Year Tale of Man Versus Mountain

Illustration by Jared Boggess

On one side, a rock wall shoots a hundred feet into the sky. On the other, a hundred-foot drop onto jagged rocks and cold, crashing Pacific Ocean waves. Between them, there is 20 or so feet of twisting road, one lane each way, with no margin for error. Which makes for a frightful proposition when the northbound 18-wheeler dead ahead drifts into the opposite lane. It's come around a curve so sharp that five seconds ago there was no 18-wheeler, just a view of infinite sea and a blind turn around the edge of San Pedro Mountain … now, well, there's nothing to do but tap the brakes and hope the rosary hanging from the rearview mirror serves its purpose.

Ggggrrroooooosssshhhh … the semi roars by, safely but close enough to smack with a left jab through an open driver's side window. The road doesn't ease up after that. It's three more minutes of threading between mountain and cliff, trusting that the dozens of drivers about to tear past keep their hands at 10 and 2 and fight the urge to stare too long at the sunset. It's fitting that this stretch of California Highway 1 is called the Devil's Slide, the way it tempts us with such a satisfying scene. Because all it takes is one bite of the apple and …

But the mountain has shown mercy today. And soon the road straightens and slopes down to rolling flatlands. A couple more miles south, past the coast-side hostel and the ranch-style houses and the Mormon Church, a right turn into a narrow road leads to sea. And perched over the sand and the water is the Moss Beach Distillery, pouring drinks since its days as a Prohibition speakeasy.

It's packed this evening. But there is an open seat at the bar, beside four men in jeans, work-boots and light jackets. They have broad shoulders, thick necks, and calloused palms. A bartender named Melissa Vega slides them fresh pints, and they eagerly take their first gulps. They lean forward on elbows or slouch into chairs, with the serious eyes and relieved grins of hard-earned fatigue.

You guys working on the tunnel? Vega asks. One of them answers Yes. She asks them how the digging is going, and they reply that it's been rough. They say something about unexpected rock formations and something about the holes you need to drill for dynamite sticks and something about support structures and so on and so forth.

There was something on the news about that tunnel, the twin tubes that would cut through San Pedro Mountain so nobody would have to drive Devil's Slide anymore.

They started digging the thing some months back, in September 2007. There was a whole ceremony at the construction site then. “When opened to traffic in late 2010, these state of the art tunnels will finally provide a reliable connection for coastal communities,” Caltrans gushed in a press release. “It is fitting to mark the beginning of the end to the Devil's Slide problem by a public celebration.”

Look around the restaurant — everybody here knows about “the Devil's Slide problem.” That stretch of Highway 1 got its name because of the rockslides that bury the roadway every few years, shutting off the main artery connecting San Francisco and San Mateo County's coastal towns, home to the best beaches this side of Santa Cruz. The Slide's irritability has often doomed passage around the San Pedro Mountain's Pacific coast edge. Less than 20 miles south of San Francisco, the mountain is a 1,000-foot tall barrier, sitting at the northern tip of the Santa Cruz Mountain Range and occupying the western part of the peninsula's corridor. Eight times over the last century, the mountain's fury has closed the Highway 1 route for weeks or months.

Vega certainly remembers the last one. It was 2006, and her 20-minute commute from San Francisco turned into a 90-minute, bumper-to-bumper affair that looped around the mountain, south on Interstate 280, then west on Highway 92, then back up north on Highway 1. And after all that, she'd walk in to find an empty restaurant. Potential patrons in San Francisco, Marin County, and the East Bay wanted no part of the San Mateo County coast. The Distillery lost 75 percent of its revenue over those four months that the road was closed.

When the rockslides weren't clogging the artery, the accidents were. The Distillery staff always knows when there's a crash on the mountain by the sudden drop in customers. Other locals — those with living-room windows facing the Slide — tell stories of watching cars plummet into the ocean, and sheriff's deputies repelling down cliffs to rescue people trapped in vehicles lodged between big rocks.

It's as if the mountain takes offense at man's efforts to cross it. And these tunnelmen, sitting at a bar after a day of trying to cut a hole through its gut, know it. For more than 150 years, the mountain has defended itself with waves and rockslides and fog. Now, too, it fights with the secrets it keeps inside itself. As work on the tunnel progressed, this has made the mountain dangerous in brand new ways. One of the men looks up at the bartender. This is gonna take way longer than anyone expected, he says.

Ages ago, when San Francisco was an infant metropolis, its growth depended on taming the mountain, the lifeline to the grain and cabbage and cheese and potatoes. The march of progress brought new tools, but none ever quite up to the task, none a permanent solution. The mountain is still in the way, isolating the produce and beaches of the south from the commerce and bright lights of the north.

Until, finally, man begins the final siege on the mountain. Right after this beer.

The man grunts as he picks up the sack, heavy with grain. Forearms flexed and brow furrowed, he tosses it onto the pile with the rest. Then his eyes lock on to the next sack 100 feet up. It's lying at the edge of a cliff. Somebody up there gives it a heave, sending it skidding down the rickety wooden ramp that ends at the ship's deck.


The sacks are due for San Francisco. Ever since they discovered gold up north a couple decades ago, all sorts of folks have poured into that city, each bringing a new mouth to feed. The crops, though, are on the other side of the mountain, grown in the fertile earth along the San Mateo coast. To transport the produce, there are two options by land: a long, circuitous trek around the southern tip of the mountain range, or a northward slog through the mountain's rocky wilderness. But the most efficient route is by sea, around the peninsula and into the Bay. Which wouldn't be a problem if there were any accessible harbors nearby. But there are only cliffs.

So a few farmers built these chutes to get their produce onto the ships bound for the boomtown. They were a response to the mountain standing in the way of developing markets. The ramps were a massive construction enterprise, but worth the trouble — owning a chute means collecting fees from every farmer who needs to use it. That is, as long as it's built sturdy enough to withstand the pounding surf. The waters are not as generous as the land, and the ship sways like a drunk pendulum. It's an innovation that solves some problems, but is far from a perfect solution.

“Grab the bucket!” a man shouts. Building up friction on its slide, a sack has burst into flames. This happens on occasion.

San Mateo Supervisor Ted Lempert sees his district suffocating. A few weeks back, in January 1995, a storm unleashed the full power of the Devil's Slide. Tons of rock, heavy with moisture, crashed into the ocean and covered the roadways. By the time county officials could measure the damage, a long stretch of Highway 1 had sunk five feet. It would be closed for months. Commutes would lengthen. Tourism would stop. Restaurants, beach-side boutiques, and ocean-view inns would lose money.

The phone in Lempert's office rang and rang and rang over the coming days. What are you going to do about this? Constituents demanded a solution, and Lempert had none. Worse, Lempert had been the most vocal opponent to the county's long-standing official fix to the Devil's Slide problem: a highway through the valley to the east of the mountain. He'd echoed environmentalists' claims that the so-called inland bypass would be an ecological disaster. But protecting nature doesn't seem as important to folks when they can't drive to work or are about to lose their jobs because their employers are hemorrhaging money. At least one “Impeach Lempert” sign has already popped up along the highway.

He sits at the head of a long table inside the San Mateo Board of Supervisors conference room. Beside him is Ruben Barrales, the only other supervisor to oppose the bypass. And before them are eight of the smartest geologists and engineers that Lempert could corral. Lempert is out of ideas, but perhaps one of these experts can think of something. A Hail Mary, he figures.

Caltrans brass, as well as almost every local official, is pushing hard for the bypass. Generations of them had given buckets of political sweat and blood to the cause. The proposal first emerged during the 1950s highway boom. Americans, with money in their pockets and shiny cars in their driveways, were taking to the road. A mammoth six-lane highway, parallel to I-280, suited these sensibilities. San Franciscans and Oaklanders could pile their families and picnic coolers into Chevrolets and trek down to the beaches of Half Moon Bay, patronizing local business along the way.

But as the environmental movement of the '60s and '70s gained steam, opposition to the bypass swelled. Not only would the project destroy the valley's ecosystem, the activists argued, it would trigger the kind of subdivision development boom that could wipe out the Bay Area's final frontier of rural life — the ranches, the fields of apricot trees, the lush rolling hills. So the activists sued the county, on environmental grounds, tying up the proposal in courts for decades.

Caltrans relented a bit. Seeking compromise, officials scaled down the plan to a two-lane highway. But the activists kept up the blockade. They had their own proposal, a Marine Disposal Alternative. The MDA was no less ambitious than the bypass. The project would stabilize the Slide by widening the mountain's base with a manmade earthen foundation sloping from the cliff to the water.

Geologists found this idea absurd. It would be a temporary solution, at best, lasting only until the newly formed lower slope succumbed to the inevitably violent erosion. Still, Caltrans had to at least make it seem like they were considering this alternative. So in the early 1990s, the department sent an exploration team to survey the area. A group of three or four scientists maneuvered a whaling boat through the waters below the Slide, deploying a bottom-sounding device to locate its base. Like most days, the surf was ferocious. It flooded the deck. Caltrans officials overseeing the project from the shore watched in horror as the boat capsized. The scientists managed to swim to land. And that was the end of the Marine Disposal Alternative.

As Lempert's experts begin pitching their ideas, though, it soon becomes clear that even the brightest minds can't come up with anything much better. Raise the roadway! Except that doesn't address the unstable cliff face that makes it vulnerable to collapse. Install drainage holes to keep the rocks light and compressed! Except all it takes is one big rainstorm to overwhelm the setup. A viaduct! Except the relentless tides would clobber the construction, then eat away at the elevated roadway's columns.

And on and on it went. Eventually, a bearded man near the door speaks up. His name is Doug Hamilton, and he is a geologist. He was looking forward to this meeting. He was on his couch, watching the news when he learned about the rockslide. Curious, he pulled out some aerial photographs from an old project he'd worked on around there. And that's when he saw it. A possible shortcut. From the area north of the Slide to the area south of the Slide. Right through the mountain.


He pitches the idea. Soft-spoken but with an air of confidence, Hamilton explains that a tunnel would be a permanent fix to the road, that its environmental impact would be negligible, and that its cost would be comparable to that of the bypass. Lempert is hooked. So is Barrales. They hadn't heard of this possibility before. Caltrans hadn't built a tunnel since 1964. Back in the 1970s, a Caltrans geologist had floated the idea of a tunnel for Devil's Slide. But the department, full-steam ahead with the bypass, quickly shot down the proposal after preliminary evaluations, claiming that it would cost too much. The idea never resurfaced.

Until now. Lempert and Barralles ask around the room for reasons why the tunnel wouldn't work. But they find no serious dissent. Lempert feels a surge of relief and excitement. He doesn't yet know how it will happen. Doesn't yet know of the political wrangling ahead, the grassroots campaign and the ballot measure and the lobbying for federal funding.

Lempert's mind is calm as he strolls out of the conference room. All he can think is that he's found a solution to the Devil's Slide problem. Whatever obstacles lay ahead, that's for tomorrow.

The next day should be easier. By then the road should level and begin to decline. The horses are tired from the steep climb. This part is the hardest, they say. It's Day One on the Half Moon Bay-Colma Road, which the newspapers called “as treacherous a piece of road as can be found. Death stalks in front and lurks behind in every foot of the climb to the summit.”

The summit must be near, but it's hard to say with all the fog. Not that the thick white haze is unwelcome. The wagon teeters with every bump over the rocky terrain, and it's probably best that the drop beyond the cliff stays hidden. For sanity's sake. The lifeless wagon up ahead, though, has come into view. It sits on the side of the trail, abandoned and with a busted wheel. What happened to those folks? But there is no time to linger and wonder. It is perhaps another full day's travel to San Francisco.

They've called that place the Emporium of the Pacific, full of wonder and jobs and brothels. The depression of the Reconstruction has passed, and this city, as far from that Eastern carnage as you can get, seems an ideal place to build a life.

So there is much ground to cover before nightfall, when the mountain turns into a cold, howling Golgotha. In those hours, the wilderness is in control. And there is nothing to do but lay prostrate at its feet, praying for mercy.

Blame the frogs. There wasn't even supposed to be a bridge here. The original plan was that a normal road would lead into the tunnel's north portal, which meant filling in this corner of the Shamrock Ranch with concrete. Early environmental reports, though, noted the presence of endangered red-legged frogs. So the plans changed. Now there's a thousand-foot bridge going up and an official protocol for what to do if any of the little guys wander onto the construction site. Find a bucket — one of the specially designated frog buckets — drop it over the frog, then phone whichever of Caltrans' three official biologists is on call that day. A rescue team mobilizes and transports the animal back to its habitat with a stern warning.

But frogs are the least of Richard Nutt's worries right now. An engineer, his top concern is making sure that the two sides of the bridge meet in the middle — a fundamental aspect of bridge building. The frogs, though, have complicated matters.

Generally in bridge-building, especially with bridges that curve like this one, workers erect a temporary framework below where the bridge will span. The workers build on top of that scaffolding, then remove it once the project is complete.

That framework between the bridge's two pillars, though, would have sat right on top of the red-legged frog pond.

Nutt's strategy, then, is to build directly outward from each pillar, as if expanding the horizontal bar on a capital “T,” a method called the “segmental technique.” But the two spans do not automatically meet in the middle: Without supportive framework, the further out each span goes, the more it sags from the added weight. Each new segment added to the span must account for the sag created by the previous one, like an archer aiming just above the target in order to hit the bullseye.

So there is Nutt, sitting in his Sacramento office, looking at a bunch of numbers on a computer program. The fate of the Devil's Slide bridge rests on this program and the man using it. Nutt's competency, you don't have to worry about. But the program, well, just five or six years ago it wouldn't have been able to handle the construction of a curved bridge. Because curved bridges flex downward and also twist sideways, which is an insurmountable complication for a program that calculates in only two dimensions. But the computer has since been taught new tricks, including working in three dimensions. Technology has turned a corner, becoming so efficient that man can afford the luxury of developing a consciousness of nature — in this case the luxury of frogs, treating them not as another obstacle, but as neighbors on the mountain. The frogs caught man at the right time.

Nutt inputs various measurements into the computer and the computer spits out directives for the machines erecting the next segment. The spans extend as the concrete dries, both sides reaching toward one another, leaving the land underneath untouched.


The long days aren't so bad — there's a crisp breeze and ocean view. The pay is meager, but enough so the children don't starve. And after years on the job, the weight of the hammer becomes familiar. No, the hardest part of working on this railroad is the rebuilding. The glory and most of the money go to the bosses, the men at the top of the Ocean Shore Railroad Company. But there's a pride in looking back after hours of pounding spikes and seeing those iron rails stretch back. Seeing the progress.

So it feels like a punch to the kidney, clocking in this morning only to find out that an overnight rockslide has torn apart more than 200 yards of track. There is at least half a day's worth of debris to clear. And after that, the hammer will pound a spike where a spike had already been pounded.

This railroad was supposed to be a marvel, 1,500 volts powering trains down two tracks along the coast, barreling through the mountain at the San Pedro Point tunnel. Then the earthquake hit. And the investors figured their money was better off in some crumbled hotel or restaurant or civic project than in a railroad that keeps breaking. Rebuilding the greatest city in the West offered both moral pleasure and sure profits. The railroad will be single-track now, and the trains will be powered by steam.

But that's all still a long way off. The hammer feels heavier today.

The mountain is under siege. For months, the workers have blasted through it with dynamite and burrowed through it with excavators. They've set up camp, spraying the tunnel walls with concrete and installing bulky ventilation systems. The men are convinced they've figured out the mountain.

But the mountain has unleashed its array of defenses. It flooded the men's equipment with water. It released ungodly tectonic pressures to squeeze the tunnel so that the men had to retreat and suspend their attack for more than a month, until the mountain had no more force to exert. And it ambushed the men with unexpected rock formations.

Today, for instance, is supposed to be a drill-and-blast day. But the rock face was too soft and holes won't stay open. More alarming, blasting into weak rock risks fracturing the surrounding rock, potentially causing the newly opened tunnel face to collapse in on itself. So the huge drilling machine must slowly reverse its way out of the tunnel. Time burns. The mountain holds its ground.

This isn't supposed to happen. There was a plan. Geologists like Doug Hamilton extracted long, tubular rock samples from two dozen or so strategic intervals in the tunnel's path, effectively mapping out the geologic conditions of the mountain. Engineers like Dan Zerga used that data to design support systems based on the varying rock formations expected, with separate specifications for the strongest rock, Category 1, up to the weakest rock, Category 5.

But when the diggers, the Kiewit construction guys, burrowed into the mountain, they were caught off guard. They ran into, say, Category 3 rock and Category 1 rock when they just expected a block of Category 2 rock, and so on. This confused the whole operation.

Support systems had to be switched to match the new conditions. This cost time and money. Kiewit had won the Caltrans contract with a $272 million bid, $50 million cheaper than the next closest offer. But that bid did not account for all this new support construction. So with each new safety structure, Caltrans' bill ballooned.

As the anticipated costs and delays grew, Caltrans cited the unexpected “geologic conditions.” Hamilton took offense. Zerga didn't understand it either. Any professional construction outfit, they thought, knew that geologic blueprints were mapped out in intervals, and that a good faith bid would account for the inevitable rock mixtures. Especially when the project employed the design-as-you-go principles of the New Austrian Tunneling Method, which Caltrans' project manager Skip Sowko once described as: “every time a piece is excavated, the mining engineer looks at the rock fractures and the soil types to evaluate what methods to use to support the excavated ground.”

But it's all federal funds anyway, so who can complain? The important thing is getting this next machine into the mountain. It inches through the dirt, engine rumbling. Deeper into the mountain. The natural light is gone now. Only a dim yellow glow from lanterns hanging like Christmas lights illuminates the machine's steady progress.

The machine is a roadheader, 50 feet long, and nearly half of that a trunk-like snout. At its tip, a thick steel log covered in spikes — a terror for loose rock. This is the workhorse, responsible for most of the digging.

The machine reaches its foe. The rock face stares back with a sinister silence. The machine strikes. Its spiky log spins with a growl, tearing away at the mountain's gut. The shredding rages on and on, like a boxer on a furious offensive.

Then the crumbling slows. The tumbling rock bits have dwindled to a trickle. The mountain has applied its best defense. The rock face has turned hard.

If the mountain will be conquered, it will bleed every dollar and every day it can out of its conquerer. The men who make the decisions know that there is no more taste for delays, no more time to keep rolling their machines in and out of this hole. The roadheader stays in the game. It grinds away, inches at a time, with solid rock and man's historical failures standing before it. But behind this machine, there's now limitless money and generations' worth of technological innovation — 150 years of human progress driving it forward, grinding the rocks and the failures to dust. Until there is nothing more ahead, only daylight, and it is almost as if there was never anything in this long hole to begin with.


The car is idling by the sign:



The drive changes from this point on. They say the northbound road is impassable, a haven for terrible wrecks. More than 250 curves, they say, many of them hairpin turns and backward turns and turns with angles never meant for automobiles. There are ski-slope inclines and over-eager boulders and potholes inside potholes. The road plays hell on even this brand-new Model B. One magazine has said, “Even with a thoroughly reliable driver and trustworthy car, Pedro Mountain road is in such poor condition that anyone going this way is simply inviting disaster.” (Luckily, an army of men starving for work and New Deal money has started constuction on the coastal highway that will one day render this broken road obsolete.)

But those who have made it through speak of dazzling views and air that smells like what Eden probably smelled like.

The car accelerates …

… And glides up the bridge, coasting into the tunnel. The portal comes out of nowhere, blended into the mountainside with its green and brown walls, artificially textured to match the environment around it. Those walls were designed by the same guy who crafted the rocks for the Indiana Jones ride at Disneyland. This tunnel sure feels like a ride, an amusement now, tamed but pretending at peril — adventure as ornament.

The amusement cost around $450 million, and just opened, in March 2013 — $175 million and two-and-a-half years past projections. But the Devil's Slide problem has finally been solved, to huge fanfare. “The People's Tunnel,” many call it. But the GPS on the dash lists it as the “Tom Lantos Tunnels.” Whatever its name, it's a smooth drive and a straight shot for nearly a mile. This mountain must have been a hell of an obstacle for them to pump this much money into punching a hole through it. Man's cold-blooded efficiency over time supplanting the adventure, the peril. Certainly, there must be a history of struggles here, all forg— Oh, this is a good song, turn it up.

Boys tell stories 'bout the man / Say I never struggled, wasn't hungry, yeah I doubt it …

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