Echo of a Cataclysm

What ancient floods left behind

We must begin by remembering beyond history.

—Paul Shepard, Coming Home to the Pleistocene

THE TOWN OF Missoula, Montana, begins when a steep fifty-mile corridor of pine, fir, and tamarack ends, at the site where the Clark Fork River exits Hellgate Canyon. French fur-trapping voyageurs called this confluence Port d’Enfer, or Port of Hell. In their own language, the Salish called the area “the river of ambush/surprise” or “place of rushing water,” stitched together by white settlers into Nemissoolatakoo, which is how we think Missoula found its name. In the early 1800s, the Lewis and Clark expedition passed through the area heading west. On their return near Pine Creek, Idaho, along modern-day I-90, Meriwether Lewis named the Clark Fork “in honour of my worthy friend and fellow traveller,” giving the ancient river its contemporary name. Where the Clark Fork River spills out of Hellgate Canyon into Missoula today, a university town sprawls.

A palimpsest is a manuscript on parchment where the original text is scraped away and replaced by new text. The first layer, imperfectly erased, seeps through into the next, making traces of itself visible. With or without us, landscapes are rarely different. No matter how many layers or erasures take place, the past seeps through.

During the last ice age, the Clark Fork poured into a valley blocked by an ice dam. Where the dam blocked the river, near Sandpoint, Idaho, the valley filled in, creating a prehistoric lake with a volume equivalent to Lakes Erie and Ontario combined. When that ice dam burst—an estimated 80 to 120 times over thousands of years—each rupture was a biblical deluge. The floods carved, over and over again, the Columbia River Gorge on the Washington and Oregon border 450 miles away. They scraped the Scablands in eastern Washington down to bare rock, leaving ripple marks and potholes visible from outer space. Linear strandlines that mark centuries of changing water levels are terraced into the surrounding hills of Missoula today.

One mammoth expert claimed that after each flood, the Columbia River “carried several times more water than all the rivers in the world combined.” I want to know what else it carried. Topsoil, icebergs, entire herds of mammoths? In some sections, the flood levels were five to six hundred feet high, skyscrapers of water hurling sixty-five miles an hour across the Rocky Mountains on a path to the Pacific Ocean.

A valley capable of holding a lake that size is capable of holding other things too. In Missoula today, it’s common for an inversion to trap cold air fronts or accumulated air pollution between the valley walls. This creates a low-hanging ceiling of clouds that persists for days or weeks until temperatures shift or big winds unclog the air mass.

During one such stretch of weather, while an inversion hung over the city, landscape photographer Brian Christianson hiked up Mount Sentinel, a peak that helps form Hellgate Canyon, thinking the light might make a good shot. Near the top, the Ice Age Floods Institute has a marker designating the lake’s highest level. That day, it also marked where the inversion ended below and blue sky continued above.

“I stood looking out over the clouds stretching in every direction,” Christianson explained, “and thought, there she is.” The ghost of an ancient lake claiming the footprint of her old valley.


THE GHOSTS OF other prehistoric lakes fill the North American landscape. Places like shallow Lake Tonawanda in western New York, whose drainage created Niagara Falls, or Lake Agassiz, the largest glacial lake in North America, whose shadow stretches from Manitoba to northern Minnesota. These lakes ebbed, flowed, and drained at a time when North America was a cold soup of ice and glaciers. But only Glacial Lake Missoula burst, again and again across millenniums.

The reverence is not in that it existed, but that it ruptured and what, our imaginations are left to wonder, was caught in its path. And who was there to hear it?


SOMETIME IN THE FALL of 1644, my ancestor Hans Olsen Aasen went hunting in the hills east of Røros, Norway. Today the slopes are bare, but when Hans set out that day, he walked for miles under birch and spruce. Legend has it that Hans came across a herd of wild reindeer grazing on moss. I like to imagine a ray of light cutting through the canopy. Reindeer flicking their ears, pawing carefully at the thin soil, aware Hans is watching them, as I’ve watched Hans in my mind, raising his musket and firing. The herd scatters, kicking clumps of moss. One poorly translated text described what Hans saw next as “stone had the color of gold.” Another said it was “a glint of copper ore.” And it was. Enough native copper was below the surface to support mining operations for the next 333 years.

Even if he couldn’t name it, Hans would have known his discovery was valuable. A cult of sacred awe surrounded metals in preindustrial cultures. Up until the end of the Middle Ages, Europeans sinking new mine shafts accompanied the act with rites and ceremonies. Long before that, when iron was discovered and collected from rare meteorites, these precious materials were associated with gods and coveted by royalty.

When I traveled to Røros in 2015, I saw this reverence displayed on the local church steeple. Where you’d expect to see a Christian cross, the mining company placed its logo instead: a hammer and chisel looming over the Venus (♀) sign. The Greeks associated the celestial body of Venus with copper and feminine beauty. Ancient civilizations around the world tracked its path in the sky.

I returned home thinking less about the mechanics of mining itself, and more about how long humans have been digging up the earth and telling stories about what we find inside, about the landscapes that shape our imagination.


Topographic evidence of the Missoula floods on a portion of Washington’s Cheney-Palouse scablands.
(Courtesy of Daniel Coe / Washington geological survey)


WHICH IS WHY, a few weeks later, I was tracing my fingers along the spines of geology texts at the University of Montana library in Missoula. It was a July afternoon. While other graduate students floated down the Clark Fork River, I was looking for more stories about historic mining cultures. The library windows looked out at Mount Sentinel shimmering in the heat, and I was getting ready to leave when I saw a small, cracked red spine that didn’t look like other books around it.

The title in gold serif letters read Report Book for Mining Engineers. I opened it slowly, revealing a workbook designed to document prospective mine sites in the early twentieth century. It was shaped to be carried in a pocket next to the nub of a pencil. After a century fossilizing on the library shelves, it remained tauntingly blank, filled with hundreds of unanswered questions:

6. Is it good holding ground on both walls? . . . . . . . . . . . . . . . . . .

11. Is the outcrop of the vein exposed at surface? . . . . . . . . . . . . . .

90. What are the healthy and unhealthy seasons? . . . . . . . . . . . .

111. State the percentage of copper therein contained. . . . . . . . . . .

I am a poet by training, not a scientist. Where the author expected logic, I saw room for curiosity. The questions focused on building capital, not understanding the consequences of removal. But taken from their original context, the formal tone sounded earnest, almost tender, in their exactness. What makes something a healthy season, I wondered, and how did light catch that vein of ore on the surface? What was it like not just to take these measurements, but to stand next to the spaces in question before their removal? Before the land is pulled apart in such a way that it can never be put back together? And how does that blank space become a witness to what we’re left to fill in on our own?


BILLIONS OF YEARS ago, a young planet in our early solar system collided, most likely with another planet, sending a 15.5-ton chunk of its iron-nickel heart on a trajectory toward Earth. Between 13,000 and 17,000 years ago, that iron heart traveling 40,000 miles an hour struck an ice sheet in Canada. From there, the former planet traveled south on shifting ice floes to prehistoric Montana, where one of the Lake Missoula floods—using the power of several thousand Niagara Falls—dropped it outside modern-day Portland, Oregon.

The meteorite is sacred to the Clackamas, who call it Tomanowos, and viewed the rainwater collected in its cavities as a powerful source of purification and healing. In the 1850s, the Clackamas were relocated by the U.S. government to the Grand Ronde Reservation, removing them from their ancestral lands, which the Oregon Iron and Steel Company later purchased. This didn’t stop a miner named Ellis Hughes from dragging the meteorite on a custom-made cart onto his nearby property in 1902. He charged visitors a quarter to peek at what he renamed the Willamette Meteorite. Oregon Iron and Steel promptly took Hughes to court, and the judge ruled the company, not Hughes, as the rightful owners. Today, the meteorite is on display at the American Museum of Natural History, where a decades-old agreement between the Confederated Tribes of Grand Ronde of Oregon and the museum guarantees the tribe ceremonial access to what has been rightfully theirs all along.

The planet that became Tomanowos formed and fragmented before our own planet finished forming. Its remnants circled the sun through the rise and fall of multiple civilizations before entering our atmosphere and colliding with Earth. Like the floods, the arrival of Tomanowos lives outside the limits of our imagination, brushing the depths of what it means to respect the unknown and touch what we can never truly comprehend.


A CENTURY AGO, geologists shrugged at the idea that a cataclysmic deluge existed outside religious mythology. They preferred uniformitarianism, a comfortable theory for the time that assserted Earth had changed in uniform ways throughout history. In other words, no sudden movements. Charles Darwin relied on it for his gradual evolution theory of species over time.

The naturalist J Harlen Bretz wasn’t convinced. In 1922, he’d noticed something strange about an area in eastern Washington he’d begun calling the Channeled Scablands. Out-of-place boulders and unnatural sandbars. Things that didn’t conform. He returned summer after summer with his family packed into their Dodge sedan with a tent tied to the front bumper. In 1923, Bretz published a paper proposing that a catastrophic flood had shaped the area, calling it a debacle that swept the Columbia Plateau. The scientific community shrugged and would continue to do so for decades.

In his 2002 dissertation on Lake Missoula, Daniel Berger wrote that, in studying the prehistoric lake, he was looking for something “vast from which I can extract my own holistic sense of the world.” By then, it was widely accepted that Lake Missoula had burst not once, but many times, and J Harlen Bretz, like so many pioneers in their field, was ahead of his colleagues in both evidence and imagination about what was possible. Today, you can sip the Lake Missoula Breakfast blend at the Lake Missoula Tea Company. The KettleHouse Brewery sells a Lake Missoula Amber Ale. The myth of the deluge is very marketable in the town sitting on the lake bottom of its origins.

I asked Berger why the floods captured his imagination enough to write an entire dissertation about them. He put it in terms of human scale. Rarely, he explained, do you have a geologic event with so much impact that you could say it lasted from the time you got home from work on Friday to the time you finished brunch on Sunday. That’s how quickly the lake emptied across hundreds of miles and millions of acres.

I’d looked at dozens of studies and maps re-creating the flood’s path, competing for comparisons about how to describe the sound, the speed, the impact. What are we trying to do? I wondered, reliving something so deep in the past. Why do we reach for it? When I asked Berger a version of this question, he paused and then said, “I think it’s the same way humans are obsessed with car crashes. We’re curious as long as we can watch from a safe distance.”

A few months after our conversation, on a flight to Missoula, I met a man who worked as an archivist before discovering a more lucrative career installing lawn sprinklers. When I told him that most of the people I talked with about Lake Missoula confessed at some point a desire to witness the floods, he jumped in. “Maybe it’s like a car crash?” he offered, echoing Berger’s metaphor. Maybe we’re all just voyeurs, dwelling in the safety of the present while dreaming of the dangerous past, tracing the origins of stories from the passenger seat. I wanted to ask the man more, but the plane was emptying. Outside, the February hills were unseasonably bare, snow missing everywhere that year, not just in Montana.


SCIENTISTS BELIEVE ROCK flour, formed by glaciers grinding down rocks caught inside their bodies of ice, would have colored the Glacial Lake Missoula a greenish blue hue—otherworldly in our eyes, both in color and vastness.

A 2016 report by USGS geologist Richard Waitt concluded that no direct evidence put human ancestors anywhere near Lake Missoula to see that blue, or witness what Waitt eloquently described as “the immense debacles down the Columbia.” Despite decades of excavations searching for a link, tools left behind by the Clovis people all radiocarbon-date to after the last floods. The closest link Waitt was willing to postulate was that the last “ice-age watery cataclysm” coming from a flood out of southern British Columbia, not western Montana, around thirteen thousand years ago “was likely to have been witnessed” by human ancestors in the area.

In the mid-1970s, Waitt discovered a layer of volcanic ash in the Walla Walla Valley that helped the geologic community come around to the idea that there hadn’t been one, but forty, separate Missoula floods. The number has continued to rise in the years since. When I emailed Waitt, I was curious not just about the human but also the animal witnesses to the floods. Had he come across any stories in his years of research?

Waitt responded right away, “As a matter of fact, yes. Pygmy rabbits. Heard of them?” At some point in geologic time, a population near an area called Sagebrush Flats in central Washington was cut off from the larger continuous pygmy rabbit populations on the rest of the continent. “I’ve not been able to stir up real action about the idea,” Waitt wrote. So how did they get there?

The pygmy rabbit is the world’s smallest member of the rabbit and hare family. Adults weigh less than a pound. The only native rabbit species in the U.S. to dig its own burrow, they can only be found among the gentle slopes of large sagebrush areas, a landscape increasingly impacted by all things human. After all this meditation on vastness and inundation, it felt like poetic irony to contrast the floods with something small enough to cup your hands around. I find strange joy imagining a tiny contingent of rabbits, separated from their cousins, surfing an iceberg down the Columbia Gorge, destined to be deposited, along with so many other things, in a new and unexpected home.


The many paths that northern Idaho’s Priest River has carved through glacial sediment since the end of the last ice age.
(Courtesy of Daniel Coe, Washington Geological Survey.)


THROUGHOUT HISTORY, we’ve passed down stories about world-ending floods and the heroes who survived: a king named Utnapishtim from modern-day Iraq built a great ship; Noah filled his biblical ark with animals to repopulate Earth; Tata and Nena of Aztec mythology carved a cypress tree to ride out a deluge; during a flood, Manu of Hinduism tied his boat to a fish that guided him to a mountain. Every great myth has a seed of truth, something from the swamp of our earliest memories returning to the surface. If our human ancestors couldn’t witness the Missoula floods, at least we can still learn from the bones of their aftermath.

Georgia Tech PhD student Karin Lehnigk studies the role of extreme floods in shaping landscapes. When I reached out to her, she shared a study about mammoth remains found where a temporary body of water called Lake Lewis, near Walla Walla, Washington, formed during some of the floods. At one location, scientists measured the temporal lake reaching twelve hundred feet above sea level before subsiding within a few weeks. Between each flood, areas like Lake Lewis would have had time to reseed and regrow enough vegetation to bring back charismatic megafauna like the Columbian mammoths (eleven tons) and the “smaller” American mastodon (six tons), as well as giant ground sloths, just in time for another flood to carry them away.

Using new geochronology and computer modeling, researchers can estimate the amount of fresh water the floods carried into the Pacific Ocean, impacting the salinity and presumably whatever life was present at the time. According to science writer Riley Black, that same simulation can help predict how glacier floods this century might alter ocean circulation.

And these same computer models help us study geologic scars on the surface of Mars. According to Lehnigk, in a profile of her work by the University of Massachusetts Amherst, the similarity between the shape and size of the canyons on Mars and those found in the Scablands offers insight into how “large floods may have been on Mars in the even more distant past.” Even on distant planets, Lake Missoula is teaching us to see what’s possible from what’s left behind.


AROUND FOUR HUNDRED MILES from where I took the Report Book for Mining Engineers off the shelf in Missoula, moving west past the places Bretz studied in eastern Washington’s Scablands, into the steep basalt cliffs of the Columbia River Gorge, a little less than a two-hour drive from Portland, there’s a placid stretch of river next to a strip of land managed as a park by the state of Oregon where a waterfall should be.

Before it was silenced by the Columbia Basin Project in 1957, Celilo Falls—called Wy-am by local tribes—could be heard from miles away. According to the Columbia River Inter-Tribal Fish Commission, more water passed over Wy-am during spring melt than over Niagara Falls. The repeated impact of the Missoula floods shaped a fifteen-mile stretch of rapids ideal for catching salmon and steelhead, which Indigenous people did for thousands of years. When Lewis and Clark passed through, approximately 7,400 to 10,400 full-time and seasonal residents were in the area.

Maybe we’re all just voyeurs, dwelling in the safety of the present
while dreaming of the dangerous past, tracing the origins of stories from the passenger seat.

At 10:00 a.m. on March 10, 1957, the steel-and-concrete gates of The Dalles Dam closed. Water pooling behind the dam engulfed Celilo until the reverberation that salmon and humans had followed for thousands of years swallowed itself and ceased. According to the Yakima Herald-Republic, tribal members sang traditional songs as the water rose. It was the erasure of an economic and spiritual center. We cannot travel back to the outburst of an ice dam breaking open the waters above Missoula. But until that moment, it might have been almost possible to stand beside Celilo Falls and trace the sound back to the prehistoric floods.

When I pulled off I-84 on a warm November morning, dozens of ducks floated near the shoreline. Because where the falls would have started or ended wasn’t clear anymore, I imagined the ducks gathering where the pull of water used to be, as if they could still feel the tug of that unimaginable current somehow far below.

There was one other car in the long parking lot—a family using the restrooms. The highway behind me was visible and loud. So were passing trains. In front, a flat absence of memory. A small plaque on a rock next to the parking lot described the place as a “history, fishing, trading and gathering place for Indians of many tribes from time immemorial” until it was “inundated by the rising waters of Lake Celilo.” The blank space left by what was unsaid was deafening.


ONE EARLY SPRING while hiking in the Rattlesnake Wilderness, along a creek that turns into a tributary of the Clark Fork River, Brian Christianson heard something that sounded like fireworks go off. He looked up. The ice jam of the creek had broken apart and a surge of pent-up spring melt, almost six feet high, came rushing beneath where he stood on high ground, watching the creek surge. He said he’s spent many, many days in the wilderness. And he’s never seen anything like it. No one else was around to witness it.

Imagine yourself standing on the edge of Lake Missoula when the dam burst. That otherworldly blue water at your feet. Does it surge? Does the wind shift as the water tilts toward the ocean? What direction do the birds fly? Can you follow the flood storming across the Scablands, down the Columbia River Gorge, over a young Celilo Falls? What looks up, caught in mid-stride? Animals run ahead of the deluge, the collapse of a watery world around them. A monster that subsides to a river and then a stream finally finding the ocean. A torrent that sleeps until it’s time to wake up again.