The answer is, of course, a lot. A rotating crew of fifty to sixty men has toiled nine hours a day, seven days a week for three months, slowing transforming the heaping pile of dirt and rock burying a hundred feet of SR-2 into a dusty repaving operation of the kind you’d see on Any Street, U.S.A.—screeds, rollers, asphalt trucks—except this one is still under daily assault from falling rocks as the mountain keeps crumbling. And so it's being met with a second effort to safeguard the road with a massive new retaining wall and steel net to cover the raw slope and catch (or attenuate in the technical parlance) any tumbling boulders.

Yet the February 15 landslide, the biggest to hit Angeles Crest in decades, has shut down a four-mile chunk of the highway's heavily-traveled southern half for months, and it will stay closed until mid-June at the earliest. This is a rarity for Caltrans, which makes its bones fixing far-flung roads melted by wildfires or buried by avalanches; whatever you think about the speed of your local repairs, know that there are workers out there fixing minor disasters in some godforsaken corner of nowhere pretty much every hour of the day in a state like California. Estimated reopening dates have come and gone. It’s enough to make you wonder: What’s going on up there?

Harris is a senior geologist with the California Department of Transportation, or Caltrans, and he's not much for complaining as he stands at the site in late April and stares at the ragged scar left by the landslide. But it's hard to think of thirty feet of rubble—an entire chunk of the mountain, dismembered—sitting atop a road he's tasked with protecting in any other fashion. Angeles Crest is the only path traversing the entire San Gabriel range, a historic trail paved with the can-do determination of an optimistic country, a critical link for the remote businesses and residents perched among the peaks, and a world-famous enthusiast playground 20 minutes from Los Angeles. It also doubles as State Route 2, which means Caltrans is locked in a Sisyphean battle to maintain 66 miles of a road surface suitable for 55-mph traffic through a mountain range that’s actively trying to destroy it.

The rock was pressed into existence at least half a billion years ago deep underground. Eons of tectonic transit ended here in southern California sometime in the late Cenozoic with it lodged in the violent seam between the Pacific and North American plates. Those crushing forces lofted the ancient mass thousands of feet into the sky as the San Gabriel Mountains. And in February, about ten million pounds of it came crashing down on Angeles Crest Highway, where it finally became Christopher Harris' problem.

"I know that it’s important to get this reopened. There’s no reason for a road to exist unless you can use it as a road. But that," Harris says, pointing at a softball-sized rock lying in the middle of a travel lane, the latest to fall that day. "That could kill you."

The road wasn’t swept away like Route 1 in Big Sur when an entire peninsula collapsed into the sea in 2017. Angeles Crest Highway held fast—"It's a good, solid road bed, and they made it well," Harris says—and survived the debris fall mostly intact. But it’s still not safe for regular traffic, and it only takes a minute at the site to see there’s a whole lot more to do before it is. Caltrans currently estimates it's spent over half a million dollars on the cleanup so far.

Rock scalers are the advance troops in this particular battle between man and geology. They are highly-specialized climbers who scamper up the inimical terrain and use hand tools and occasionally explosives to remove any and all loose rock, some of which can be dislodged with a single finger. It's incredibly dangerous work, strung up by ropes anchored to a surface that's already experienced a catastrophic failure. But there's no other way of ensuring the mountain is out of ammunition, and no real progress can be made on the main body of the slide until this risk is neutralized.

Stabilizing a landslide zone isn't just a matter of removing the material that's already fallen. To start, you've got a great mass of loose material stretching from the road to back up the slope. Harris likens it to digging a hole in the beach—scoop out the bottom and the hole just backfills from up top, creating the potential for another slide. The trick is to get at it from above and remove anything that's loose. Sometimes, Harris says, you get lucky with a utility road snaking nearby that affords easy access. Other times, when faced with a 70-degree incline, you send in the rock scalers.

That fateful radio call kicked a sprawling, dormant machine into motion. Caltrans quickly dispatched two front-end loaders to the site in a hopeful bid to start clearing the road; once the scale became apparent, the agency sent out emergency contracts to qualified debris disposal firms. As the lead geologist in Caltrans District 7, which covers the San Gabriel Mountains, Harris went to see the disaster himself that very first day. And he immediately knew it was going to be a long process to clean it up.

So constant is the fight against rockfalls along Angeles Crest that every single day, Caltrans runs battered snowplows up and down its entire length to shove small boulders out of the road. One of those units first came upon the landslide that Friday and radioed it in. Miraculously there was no one underneath when it let go, though as Harris pointed out, there's no way of knowing for sure until you start digging. The story would have been much different had it come down just 24 hours later in the middle of the weekend when the road is packed with car clubs, nature fiends, and sightseers alike.

At around noon on February 15, a gray, drizzly Friday, the mountain could hold it together no more. In an instant, millions of pounds of dirt and rock tumbled down on Angeles Crest Highway, burying a dinky retaining wall built in the aftermath of a much smaller slide in 2006 and both lanes of the roadway under 30 feet of rubble. The force of the landslide also sent debris cartwheeling over the pavement's far edge and down the slope another 300 feet. Harris, ever the underseller, says it "probably made a pretty good noise."

The winter of 2018-19 was already zooming toward the record books at the end of January as storm after storm flew off the Pacific and cluster-bombed the mountains with flooding rains and drifting snow. It started with a single crack. Sometime in early February, a small rift opened in the earth, no more than five feet long and an inch wide at first, a few hundred feet above a particularly scenic bend in the highway just north of Mount Wilson. Tension cracks are classic harbingers of a landslide, a sign that the ground is literally coming apart. But there was no one to see the linear canary sprawled amidst the chaparral and yucca as it grew over the coming days, rain working its way down into the rock and unlocking the slope from within.

Looming 10,000 feet over Los Angeles like an unsteady drunk uncle, the San Gabriels are among the fastest-growing and fastest-eroding mountains in the world, vomiting loose rock with prodigious enthusiasm. Slides occur regularly across the range's 970 square miles of crumpled earth. It's not so much a question of when they fall but where they land. That natural instability is exacerbated by some truly wild weather swings—hot, dusty, distinctly Mediterranean in the summer, and winters where it's not uncommon for a foot of rain to fall in a day. It's through this gauntlet that California built Angeles Crest Highway in stages between 1929 and 1956.

After a few weeks—all the while, the rains kept coming, triggering smaller slides and further complications—it was time to bring the spider out to play. A spider excavator is an all-terrain digger sitting on a quadrangle of articulating arms and anchors that allow it to sit mostly level on slanted ground. It quite literally climbs its way up from the bottom, a many-ton mechanical arachnid heaving itself skyward for the better part of an hour to reach the top of the pile. Once there, its brave operator removes bucketfuls of dirt and rock to slowly but surely erase the landslide from above.

He works the controls with his seatbelt off and the door open in case he needs to jump free as the rig falls away beneath him; even when it's "anchored," it's forever slipping towards the precipice. Seeing the spider perched 200 feet above his head, one visiting California Highway Patrol officer asked, "Does he have a harness for those balls, too?"

Caltrans

The spider excavator was on site for most of March, working its way down to fully expose the dramatic scar left by the slide. Crews rigged up a pulley system to fling diesel up the mountain and cut down on time-consuming fuel stops. Back down on the road, workers could begin tackling that 30-foot pile of regolith. Enough material to overfill the Goodyear Blimp was gradually carted down the road to a U.S. Forest Service-approved dumping site where it's piled in a massive mound that will be seeded with native grasses and returned to the landscape. The battered pavement of Angeles Crest Highway finally emerged at the end of the month, as did the stumpy old retaining wall—bent and splintered but still intact. Harris will admit to smiling at the sight. The slide's mass is officially gone. The danger, however, is not.

Jonathan Harper

The Plan to Fix Angeles Crest Highway Caltrans couldn't pick a better front man for the San Gabriels than Christopher Harris, whose energy is a perfect match for the mountains—latent, reserved, and always ready to strike down a silly question. He's been with Caltrans for 28 years, seen a lot over those three decades. He's not prepared to let something like the biggest landslide in recent memory on Angeles Crest Highway push him into a philosophical discussion on the fight against nature itself. He just wants to get it done.

Jonathan Harper

I met Harris walking down the road toward the landslide on a gorgeous Monday morning after being shepherded through two police roadblocks that exist because one simply doesn't do the job. The mountainside came down in the middle of a sweeping right-hand bend above a tight canyon; approaching from the south provides a perfect view of the entire slide site both above and below the road. The scale is such that it looks curiously small until you pick out the tiny dump trucks shuttling back and forth across its face. Where once existed rocks, plants, and animal burrows there is nothing, a void, a giant halfpipe a hundred feet wide gouged deep into the earth and scored by unthinkable violence. Get closer, and the remaining slope is so steep that you can barely see fifty feet up when standing directly under it. I could only think one thing: That spider operator is f*cking insane. But Harris has an even more daring operation to impress a soft-handed lowlander. The week before my visit, a natural spring opened up in the middle of the newly-exposed rock face, spewing 14 gallons a minute and digging a destabilizing cave. It was too dangerous even for the rock scalers—so the contractor used a construction crane to lift workers up to the site and seal it.

Still, with its intact road and paving equipment, the worksite manages the passing resemblance to any municipal construction project until I notice the watchman. He's standing on a berm across the road from the slide, staring intently up at the windswept slope, and his entire job is to watch and yell "ROCK!" the moment he sees something move. He does not break focus. There's no way to completely stop the rocks from falling; Harris says it's the wind that makes him the most nervous. "A gust will get swept up in this channel here," he says, pointing to the halfpipe, "and literally lift rocks off the face of it." Usually they're small. Sometimes they're not.

Jonathan Harper The watchman.