EASTERN WASHINGTON—Traveling from the verdant, mossy coastal belt of the Pacific Northwest, one could be forgiven for feeling that the defining characteristic of Eastern Washington is its dryness. It's a land seemingly starved of rain in the shadow of the Cascade Mountains. But the dry landscape known as the “Scablands” actually tells a story about excess—excess of water, water that was torrential and sudden.

The Scablands are essentially wounds, still unhealed by time and erosion. They cut through the land and down into the rock after a series of unfathomably large floods unleashed by the catastrophic draining of great glacial lakes—half the volume of Lake Michigan splashed onto the land in less than a week. If you can imagine that, you’ve got us beat. The story recorded in this landscape is so incredible, it took one geologist decades to convince his colleagues that he was reading it correctly.

Inflation of the modern American vernacular has devalued superlatives like “awesome” and “epic,” but we’re going to need them where we’re going.

Our protagonist

After growing up in Michigan, J Harlen Bretz (don’t ask—the J doesn’t stand for anything) was working as a high school biology teacher near Seattle around 1910 when the geology bug bit him. Hard. He and his wife Fanny (also a biologist) explored the land around them with a burning curiosity, and he began to produce pretty impressive maps and interpretations of the marks left on that landscape by glaciers.

Bretz was keen on maps, eager to follow as the United States Geological Survey was mapping new areas of Washington. One of the results really caught his interest—it showed what appeared to be a pair of dry waterfall ledges high above the Columbia River in eastern Washington, with no source of water to be seen. Bretz couldn’t figure out what the hell they were doing there, and neither could any geologists he talked to. “Here was something that fascinated him as few things had before,” John Soennichsen wrote in his excellent biography Bretz’s Flood. Bretz couldn’t have known at the time that he just met the mystery that would become his legacy.

Before long, Bretz moved to the University of Chicago to get a PhD in geology. When he obtained it, he happily returned to the Pacific Northwest to teach at the University of Washington. It didn’t go well. His Socratic method of teaching and insistence on getting students into the field chafed his stodgy colleagues, whom he grew to despise.

And so, in 1914 the pendulum swung him back to the University of Chicago, where he would settle in. But even if Bretz couldn’t stand Washington’s geologists, he was still enamored with the state's geology. He began leading summer field courses to the Cascades and the Columbia River Gorge.

There are plenty of odd things to notice about the gorge. One that caught Bretz’s eye was what geologists call “erratics”—boulders made of a rock type that can’t be found locally. Boulders are, it needn’t be said, rather heavy, so how do they travel great distances? The only transport they hitch a ride on is ice, and erratics are commonly strewn across glaciated landscapes. There was, however, no sign that glaciers had come far enough south to reach the gorge. So why the rocks?

One of these is not like the others

It’s hot (again), and I’m nearing the end of my four-day tour through the Scablands. I've come here to see the evidence of Bretz's great flood for myself. After I convince myself that I’m probably not about to wander onto private property, I scavenge batteries from a flashlight for my dead GPS unit, shoulder my pack, and point myself uphill. I’m at a place called Wallula Gap, just south of the “Tri-Cities” of Richland, Pasco, and Kennewick, where the Columbia River flows through a huge notch in the ridgeline of the Horse Heaven Hills.

As I start down a sandy Jeep track, I’m only a few tens of feet above the river, but I’ll gain almost 800 feet before I reach the top. After a few minutes, the track turns away from the river, up into a steep-sided grassy little canyon. Cows have been here, as their footprints and gastrointestinal gifts can attest, as have humans messing around with shotguns. Thousands of years before them, coursing floodwater had been here, too. In fact, there wouldn't have been a “here” without it.

At the top, I look out over the dusty lowland. I try to picture it all underwater.

Soon, my GPS unit brings me to my target. I’ve come to see a rock. I’ve seen plenty of rock on my way up—black basalt layers from the massive volcanic eruptions that covered this entire region in floods of lava some 16 million years ago—but nothing like this one. The boulder is bright white, with small black mineral flecks and scattered lichen eking out a living on its surface. It is decidedly unbasaltish.

Scott K. Johnson

Scott K. Johnson

Scott K. Johnson

Scott K. Johnson

Scott K. Johnson

It is, in fact, granodiorite, a granite-like igneous rock that solidifies underground. To find bedrock like this, you have to travel at least a hundred miles to the north. It’s an erratic. The great ice sheet that covered Canada didn’t invade this far into the United States, though. You can’t find the chaotic sedimentary jumble of rocks, sand, and silt that ice sheets leave in their wake. This boulder, gripped in an iceberg, surfed the roiling waters of a raging flood and was plopped here on a ridge top, almost 800 feet above the Columbia River. It’s wild, and it’s true.

The scene of the crime

In 1922, Bretz tried to bring a group of students to the Cascades, but they were unable to make the last leg of the trip. Instead, they used their remaining time to poke around the Scablands near Spokane. The experience hooked him, and Bretz would return every year to further his research.

In the first couple summers, Bretz and his students mapped an impressive amount of territory, carefully surveying elevations and making observations of the many strange landforms they discovered. They made their way through a number of the dry valleys locally known as “coulees.” While these were plainly products of erosion, there were no streams to be seen. The surrounding region is composed of soft, rolling hills of silty soil, but the rocky coulees had been scraped clean of their sedimentary mantle.

As the map came together, the bigger picture was just as striking as the stark, basalt bedrock. The coulees were connected in an “anastomosing or ‘braided’” network of channels, as Bretz wrote. Braided stream channels are common where sediment-laden meltwater washes out from the end of a glacier, constantly wiggling to and fro as an abundance of shifting cobbles and mud reroute the flowing water. The Scablands channels, however, cut down into the bedrock.

The scoured channels led from the area around Spokane to the northeast, ending in the Snake and Columbia Rivers to the southwest. Many of the places where the channels met those rivers were not natural, low-lying outlets, but they instead seemed to have cut across high ridges that should have stopped water from flowing over them. In fact, this sort of unexpected behavior could be seen throughout the Scablands.

In his first two published papers, it was obvious that Bretz didn't feel comfortable ascribing the Scabland's features to a massive flood. The battle against those who interpreted the Earth’s landscapes and rocks to simply be the ruins of Noah’s biblical flood was still fresh to the older geologists of his time. Scientists worked hard to show that normal, everyday processes had slowly shaped the Earth's past, just as they do today. Any claim of sudden, catastrophic processes (especially floods!) would face harsh resistance for bearing too much resemblance to the old ignorance. Huge eruptions covering a landscape with basalt over a few million years is one thing—a cataclysmic flood carving up that basalt landscape over a few weeks is quite another.

Bretz starts out by describing the waters that must have carved the Scablands vaguely as “glacial streams” flowing from the mighty ice sheet that stopped just north of Spokane, though he eventually breaks out the word “flood.” At the start of his second paper, it’s clear that he’s trying to prepare the reader’s mind with a broad set of undeniable observations, a way to ease it into the shocking conclusion.

Following his list of observations in that 1923 Journal of Geology paper, Bretz writes, “This unique combination of topographic features of the Columbia Plateau in Washington has only one interpretation consistent with all the foregoing items. The channeled scablands are the erosive record of large, high-gradient, glacier-born streams.”

Bretz emphasized the need to keep multiple working hypotheses in mind when looking for an explanation, lest an early hunch dig you a rut. But he made it clear that he saw no viable alternatives for the Scablands. Whatever the source of water, he thought, an incredible flood related to the ice sheet must have swept across the region. After laying this scenario out, he wrote, “The conception above outlined is amply sustained by every feature and relationship of the scablands. All other hypotheses meet fatal objections.”

Anticipating resistance, he continued. “Yet the reader of the following more detailed descriptions, if now accepting the writer’s interpretation, is likely to pause repeatedly and question that interpretation. The magnitude of the erosive changes wrought by these glacial streams is nothing short of amazing. The writer confesses that during 10 weeks’ study of the region, each newly examined scabland tract reawakened a feeling of amazement that such huge streams could take origin from such small marginal tracts of an ice sheet, or that such an enormous amount of erosion, despite high gradients, could have resulted in the very brief time these streams existed.”

Referencing the old battles over whether the landscapes of northern North America and northern Europe were the work of biblical floodwaters or great ice sheets, Bretz ended the paper with a flourish.

If the battle between the diliuvialists and the glacialists, out of which has emerged our conception of Pleistocene continental glaciation, had been staged in the Pacific Northwest instead of the Atlantic Northeast, it seems likely that the surrender of the idea of a debacle [a violent flood] might have been delayed a decade or so. Fully 3,000 square miles of the Columbia plateau were swept by the glacial flood, and the [silt] cover removed. More than 2,000 square miles of this area were left as bare, eroded, rock-cut channel floors, now the scablands, and nearly 1,000 square miles carry gravel deposits from the eroded basalt. It was a debacle which swept the Columbia Plateau.

Listing image by Scott K. Johnson