This story featured in the March 2012 issue.

Photo: Reid Morth

A morning like so many on this river. Also, a morning freighted with somber purpose. Summer warmth rises like mist. Mosquitoes linger. The canoes wait in a backwater eddy where blue heron and whitetail prints stipple the mud bank. I hurry to load the boat, eager to be back on the current. A flicker calls. A pair of mergansers wing past. The sounds of Billings blend in the distance, the hum of tires on pavement. A city going to work.

Marypat settles in the bow, her strong shoulders so familiar. Before we back out of the quiet, shady alcove, she reaches forward, puts her hand in the mud, rubs her fingers together and holds them up to the light. The tips of her fingers shine with oil. We take a picture, scoop some of the slime into a plastic bag, and label it for documentation.

The Yellowstone was in flood on July 1, 2011, when the Silvertip Pipeline burst, spewing an estimated 42,000 gallons of medium crude oil into the river near the town of Laurel, Mont., about 15 miles upstream of Billings. The pipe, which carries 1.2 million gallons of oil every day, was buried about five feet beneath the riverbed. The Silvertip is 20 years old, and in those two decades the Yellowstone has recorded three 100-year flood events: the historic deluges of 1996 and 1997, and again last year. In the face of such power, a few feet of loose sediment covering a pipe is like a stud wall against a tornado—the break was a question of when, not if.

Two weeks after the Yellowstone oil spill, Marypat and I join Gary Steele on the river to help assess the damage. The compact, gray-bearded kayaker from St. Ignatius, Mont., is the principal instigator of an independent river survey, which he's dubbed the Oily River Rendezvous Project. He exudes a backwoods Mr. Natural aura at odds with his clear focus on the mission at hand. Gary is fired up, ready to document with sample bags, GPS, printed forms, and camera.

Photo: Reid Morth

"I heard about this spill and I thought, 'Oh my god, it's happening here!' I wanted to see for myself, and I knew that you could see things from the vantage of a canoe that wouldn't be covered otherwise." Steele's words come in an animated stream as he bounces between his well-used boat and timeworn Subaru, loading a spare paddle, camera, and sampling containers. He pauses to gaze at the river, still humping along at 30,000 cfs, lapping at flood stage. "I knew the oil company would try to keep people off the river," he says.

In a 10-day window after the spill, Steele managed to secure the backing of American Whitewater, cobble together some funding, and enlist a crew of kayakers and canoeists. But yesterday, when he arrived at the boat launch near Laurel, cleanup officials summarily ran him off. "They saw me drive up with a canoe on my rack and they told me in no uncertain terms to go away and stay away," he says.

That evening, Steele contacted a landowner who was more than happy to provide river access. When we arrive the next day, the landowner asks not to be identified. But as he watches us load our canoes, he doesn't hesitate to voice his disdain for the oil company's response. "The Exxon guys came through here, walked around, said there was no impact on wildlife," he says, gesturing at the underbrush. "I came down and poked around that same evening and saw a deer, a goose, a turtle, and a couple of ducks with oil on them, all in less than an hour."

He waves as we edge into the burgeoning current. The river is huge, boiling, engorged with snowpack and summer rain, pouring across Montana at three times its normal volume. I kneel in the stern, ready with a brace. It takes a few minutes before I relax enough to look around.

Photo: Reid Morth

Marypat points to the bank. A black ring of tar residue marks the vegetation a foot or two above the present river level. We pull off at the end of an island to examine the stained leaves and grass. Steele bags samples of vegetation and takes more photos. There is oil-stained wood in the logjams, oil residue in the crannies.

Immediately after the spill, Exxon Mobil went into cleanup mode, both on the river and in the press. They deployed booms, contracted jet boats, hired a crew of hundreds to contain and clean up the spill. At first they claimed to have shut off pipeline valves to stop the leak six minutes after it began. Within days, federal documents revealed that oil poured into the river for nearly an hour. Estimates of the quantity of oil spilled settled at about 42,000 gallons, a number supplied by Exxon Mobil. The company's word was all anyone had to go by, but most Montanans were skeptical to say the least. Montana Gov. Brian Schweitzer even urged landowners to take their own water and soil samples, suggesting that Exxon Mobil couldn't be trusted, and that the federal EPA, which nine days after the spill had yet to take a single sample, was dragging its feet.

The Silvertip break revealed a startling lack of oversight regarding pipelines that cross bodies of water. In the wake of the spill, federal officials admitted they didn't know how many pipeline river crossings there are in the United States, or precisely where many of them are. Finally, the U.S. Pipeline and Hazardous Materials Safety Administration released a rough estimate: 35,000 pipeline crossings in the Lower 48. Still, regulators know little about the exact locations, depth of burial, age of pipelines, or records of maintenance. If one pipeline on the Yellowstone caused such devastation, how many other pipelines on how many other rivers are at risk?

For the Yellowstone, the Silvertip debacle was only the latest incident in a continuing legacy of human-borne insults. And yet, the Yellowstone retains its wild nature. It's celebrated as the longest undammed river in the continental United States, and revered for its fishing and boating opportunities. The Yellowstone is a river that still acts the way a river is meant to act, which is to say that it erodes its banks, shifts its channel, piles up logjams, floods at regular intervals, and has no regard for property lines.

Photo: Reid Morth

Steele and I marvel at the river's unchecked force as we stutter through Billings, stopping to take samples and photographs. "It has such a wild and powerful feeling," Steele says, "even when you're going through a pretty big city." The river does feel unruly under our hull, no matter that Interstate 90 is in plain sight, and the Billings refineries squat against the skyline. I keep kneeling, brace ready.
But listen.

You can hike right to the very headwaters of the Yellowstone—a 50-mile round trip, up the South Fork of the Shoshone into the alpine tundra of northern Wyoming's Washakie Wilderness. This is grizzly and wolf country, an area farther from roads than anywhere else in the Lower 48. Here, Younts Peak rises more than 12,000 feet above sea level, its massif necklaced by the North and South Forks of the Yellowstone.

Nearby, at the permanent snowfield marking the very source of the Yellowstone, you can lie on your belly and drink the water dripping into the shallow basin, trickling away through the rock layers, glinting across the flower-dotted meadows, heading downhill nearly 700 miles to the storied confluence with the Missouri River in North Dakota. Those first water molecules are cold as ice, burning in your gut, pure and unfiltered.

Photo: Reid Morth

For more than 100 miles, the Yellowstone is as wild as a river gets. It meanders through Yellowstone Park and fills the vast pool of Yellowstone Lake, 136 square miles of water in a caldera still heaving with volcanic heat. It pours into the Grand Canyon of the Yellowstone, plummets more than 400 feet over Upper and Lower Falls, immortalized by artists and photographers over the last century and a half, where ospreys nest on pillars of volcanic ash and the river churns white through steaming sediments. It cascades on through the Black Canyon of the Yellowstone.
A rampant, exultant, spectacular run.

Where the Yellowstone leaves the protection of the national park, at Gardiner, Mont., it is still wild and raging. It pounds down the Class III Town Stretch, under the highway bridge, and downstream to Yankee Jim Canyon, full of boat-eating holes and surging boils. But also, right there, the river enters a 550-mile gauntlet of human occupation. The town of Gardiner crowds the banks. With depressing regularity, over the decades, the sewage treatment system has spewed raw human waste, thousands of gallons at a whack, into the river. One three-day spill in June of 1998 dumped an estimated 220,000 gallons of untreated sewage downstream.
Welcome to civilization.

Flowing north, the river forms Paradise Valley. From a distance, it is paradise. Rimmed by the snow-clad peaks of the Absaroka and Gallatin Mountain ranges, the Yellowstone scribes through cottonwood groves teeming with deer and eagle. The channel is full of trout, pursued by anglers in drift boats—a scene of postcard beauty. Starting in the 1950s, Paradise Valley residents mounted a two-decade effort to stop the proposed Allen Spur Dam, which would have inundated much of the valley and stifled the free-flowing river.

But after the back-to-back floods of 1996 and 1997 devoured homes and bridges, residents worked to tame the river. They built miles of levees, lined banks with riprap, erected metal walls, dredged channels—whatever it took to protect the valuable property.

Despite that, it is still a beautiful river, even downstream of Livingston, where the interstate follows the Yellowstone east. Farmland lines the banks. The Crazy Mountains jut to the north, the Beartooths to the south. Cottonwood groves, cormorant rookeries, sandhill cranes, trout rising, standing waves, playholes, gravel bars to camp on.

Photo: Reid Morth

From a boat, the highway recedes, the sounds of traffic and train whistles fade, the power of water takes over, undaunted, running as it has run through the millennia. The river is the dominant force here, and it will endure. That certainty settles in from the seat of a canoe. This is the same river Capt. Clark traveled with his men, and with Sacajawea and Pomp, during the summer of 1806, on his journey back from the Pacific.

On one bend, you can camp in a cottonwood grove, perhaps the one where Clark's horses were stolen by the Crow and his party spent several days hewing canoes out of the cottonwood trunks. Then, in Billings, the yellow Sacrifice Cliff, sacred to the Crow, rises sheer above the flow. Across the way, the electric power plant sucks cooling water from the river, and downstream the interstate ramps over the valley. Jet skis buzz the water on summer weekends.

When I paddled the length of the Yellowstone in 1992, I thought it would get boring east of Billings, that the river would turn lethargic, the landscape monotonous. I was wrong. The land opens. The sky spreads. The river stays vigorous, gleaming with agates on gravel bars, flowing under cliffs crammed with swallow apartments, cottonwood groves spreading for miles over coulees and draws. Humanity thins out. It is quiet, the stars thick. I'll take it over Paradise Valley any day.

Even there the Yellowstone is not free. Though not technically dammed, six major diversion weirs downstream of Billings deflect portions of the river's flow into irrigation canals. (Some diversions are marked with warning signs, others not. Some can be run or avoided, others require a portage.) The diversions are the asterisk in the Yellowstone's 'longest undammed' claim. Water taken from the river supports hundreds of thousands of acres of crops, mostly sugar beets and alfalfa. Between the weirs, hundreds of gasoline-powered pumps suck water out of the Yellowstone and onto farmers' fields. In the summer, it can be tough to find a camp out of earshot of the nearest pump motor.

Without that water there would be no human occupation. Downstream of Miles City, I met with Robert Muggli, whose 1,700 acres have been in his family—and nourished with water from the Tongue and Yellowstone Rivers—for three generations. Muggli, a compact and weathered, self-reliant jack-of-all-trades in his 60s, recounts his 50-year effort to build a fish passage channel around Twelve-Mile Dam on the Tongue River, one of the major prairie tributaries of the Yellowstone. With a stubborn perseverance that began as a young boy, a loaned backhoe and countless hours of free labor, he succeeded, allowing more than 50 species of warm-water fish to travel up the Yellowstone, and then up the Tongue, for the first time since 1886. It strikes me how men like Muggli, the largest irrigator in his regional district, or the landowner upriver, near Laurel, who granted us access and insight, are such willing conservationists, yet also so tied to the manipulation of the river. And how all of us are guilty of that same paradox, in a less direct way.
It is a cumbersome, lurching dance, this business of our occupation.

In early October, Exxon Mobil reopened the Silvertip Pipeline after burying it 40 feet below the riverbed. As that oil began to flow again, the proposed Keystone XL pipeline project, connecting the oil sands of Alberta (via Montana) to refineries on the Texas Gulf Coast, was subject to public hearings throughout the West and getting national attention in the press. The Keystone XL, designed to carry nearly 22 million gallons of oil-bearing sludge every day, would cross hundreds of waterways and travel through the Ogallala Aquifer on its route south. In early November, the Obama administration postponed a permitting decision on the pipeline until 2013, effectively delaying the politically charged decision until after the 2012 presidential election.

A week after Silvertip reopens, I head back to the Yellowstone on a four-day fall weekend. We paddle from just downstream of Pompey's Pillar, where Clark scratched his name in the sandstone in July of 1806, to just upstream of Forsyth. Gary Steele later tells me that when he and his survey team paddled this stretch in July, the oily bathtub ring extended 50 miles below the spill site, and oil oozed from the bank near Pompey's Pillar. Two weeks after the spill, the river had already begun to heal itself. "I was really happy we didn't find huge oil slicks and dead animals everywhere. I really didn't want to find that," Steele says.

Photo: Reid Morth

Scott Bosse, the Northern Rockies director at American Rivers, cautions that we'll never know the full impact of the spill. Exxon Mobil admits to recovering less than 1 percent of the lost oil—despite employing 1,000 workers and 39 boats at a cost upwards of $130 million on cleanup efforts and pipeline replacement. Because baseline data was never established, Bosse explains, there's no way of knowing what impact oil pollution had on fisheries, hatch success rates, or the small aquatic life forms that constitute the foundation of river ecology.

But the river cleans itself, as it always has. We detect no sign of the summer oil spill on our October float. What we do find, and what Steele also discovered on his trip, is how quickly the Yellowstone seduces us. "It's amazing how easy it is to be by yourself on that river," he says.

We portage a diversion dam. We camp on gravel bars. We collect a sack of moss agates. The cottonwoods flame yellow. Stars shine thick in the cold, moonless night sky. Coyotes carol at us through fire-lit darkness. Geese cruise overhead. The river, ebbing and clear, runs through the days and nights of fall, under our canoes, murmuring past our camps, flushing away the busyness of work and school and meetings. Like it always has.

— Editor-at-Large Alan Kesselheim has twice paddled the entire navigable length of the Yellowstone with his family, camping along the way, and has spent a week hiking to the headwaters in northern Wyoming.