IN A 5 A.M. DAZE, Kelvin and I and three other passengers leave Cali in a white diesel Chevrolet sedan piloted by a stick-figure man who claims he's the only driver heading toward the slides.

Call him Flaco. Sporting inky slicked-back hair and a caterpillar mustache, Flaco belts out the refrain to every song blaring on the stereo as he whips through the fog-obscured streets. He swerves left, skidding the wrong way around a traffic circle, and juices it up the on-ramp of a highway that switchbacks into Cali's forested western suburbs.

At 6 a.m., we reach the puesto de control in Lobo Guerrero, a multilane tollbooth commandeered by soldiers who are turning away civilian cars. We hire two bored-looking men with 100cc motorcycles to take us past the checkpoint. Soon, my driver's Kawasaki Sun is sputtering through a hyper-verdant 3,000-foot-deep canyon plucked straight from Land of the Lost. In the hamlet of Cisneros, about 30 miles from the coast, a soldier waves us to a stop.

We set off on foot. Just down the road, I meet Alessis, a spunky Afro-Colombian fishmonger from Cali determined to get to the coast in time to collect on a big shrimp harvest. Given that he's walking, I don't know what he'll do with the shrimp once he gets there, but that's his issue.

Maybe in his early thirties, maybe four and a half feet tall, Alessis bounces along with an oversized swagger and catcalls at girls twice his weight. He has leg muscles like pistons, and I have no doubt he could piggyback me all the way if I didn't mind dragging my toes.

At 7:45, after about four miles, we arrive at the first mudslide, a triangular slump of orange ferrous soil released from a steep, bird-noisy, three-tier tropical rainforest. Following Alessis on foot, we skirt the tailings close to the river's edge, stride around a languorous crowd of soldiers charged with guarding the dirt, and bop along the pavement, which resumes 100 yards away. The first four slides are virtually identical and spaced about half a mile apart. Slides five through eight present bigger challenges, fun tangles of root balls and tree trunks resting higgledy-piggledy on high plateaus of mud. Then we're back on pavement, following the double yellow line until it disappears in another barricade of mush.

At one point, we stop where two teenagers have set up a roadside lemonade stand. Alessis takes the first sip. "Mmmmm!" he says. Quenched, he flexes his biceps like a dwarf bodybuilder.

A feeling of camaraderie pervades these hardships. There are hundreds of people making their way along the ruined highway. Teenagers set down their BMX bikes to assist a chunky woman balancing a suitcase on her head. A well-dressed man, carrying his wing tips, pulls two schoolkids up a slick embankment. Everyone in the mini-migration seems to be in good spirits, but no one even approximates the skull-half-full enthusiasm of my man Alessis.

"Can you make it?" a woman calls to him.

"Of course," he yells back, throwing his hands up at the utter preposterousness of the question and mentioning an empty city bus we saw roll by. He's certain it rammed through the two-story walls of mud like a monster truck. "Didn't you see that bus?"

"Yes. But how do you know the bus isn't from this town?" she asks.

"No, no, no, it drove in over the slides!"

"How do you know?"

"Of course it drove in over the slides!"

He turns to me: "Mamacita . . ."

By one o'clock, according to Alessis's count, we've traversed 37 slides (my notes say ten). I'm feeling excited. We are a merry band of travelers! We will get shitpindled at the world's most hard-to-get-to bar!

We round a bend and—wham!—we see our last slide and the first obviously buried village. With that sight, I realize that—wham!—I am a royal ass.

The pavement disappears under a one-acre cesspool of mud and boulders and tree trunks stripped of their limbs. Various household items such as toilets and TVs float on the surface.

The mini-migration freezes. People cover their noses with handkerchiefs to block the smell of sewage. The slump is up to or over the eaves of more than two dozen homes. Rescue workers wade through the mess, hoping that someone might still be alive but carrying body bags nonetheless. Soldiers circle the foul sludge, bandoliers of shiny brass ammunition wrapped around their chests, while two yellow earthmovers scrape away at the edge.

In front of us, a mother and son, stuck up to their knees, struggle to salvage an electric air conditioner. They offer chagrined smiles as we slop past, and this sight, of all things, hits hardest.

I feel like a funeral crasher. Here they are, at what is essentially a mass grave, and, in the middle of humbly clinging to one little piece of their lives, they smile at me, a lucky twit passing through for his own sudsy amusement.

My grand quest is absurd.