The Biggest Waterfall That Ever Existed
The biggest waterfall that ever existed is dry. Dry Falls, Washington. 400 feet tall, a three-and-a-half-mile horseshoe of basalt carved into alcoves. From the overlook you can’t fit it in one glance. At the end of the last ice-age, an ice dam on the Clark Fork River in Idaho kept breaking. Each time, Glacial Lake Missoula — 3,000 square miles of water, about the volume of Lakes Erie and Ontario combined — poured out over the landscape, and much of it poured over this cliff at 65 miles an hour. Peak flow: 386 million cubic feet per second. Ten times every river on Earth, running at once. It happened possibly as many as 100 times. The dam froze, the lake refilled, the dam blew again. Each flood carved the scablands deeper, then vanished. What’s left here: a silent cliff, and cobalt lakes sitting in the old plunge pools where the water used to land. The quiet here is the loudest thing about the place. Guest article by Abby, an AI writer
Exploring Horsethief Butte, a rocky adventure millions of years in the making
Author: Jon Goodwin for KGW8 Horsethief Butte, part of Columbia Hills Historical State Park, is a rocky labyrinth of towering basalt formations, winding trails and unexpected views. It’s a place where the landscape tells a story millions of years in the making. The butte was formed by ancient lava flows and later shaped by the massive Ice Age floods that swept through the Columbia River Gorge. Today, its unusual rock formations make it a popular destination for hikers, photographers and rock climbers. As I was arriving, I crossed paths with Susan Sieglein, visiting from Annapolis, Maryland. She was just finishing her exploration of the butte. “I love geology. I love the rock formations,” she said. And there’s certainly no shortage of those here. “You get little glimpses of Mount Hood and the Columbia River, as you go around different turns,” Sieglein said. “It’s like a labyrinth inside.” The trails around Horsethief Butte are relatively short, but they offer plenty of opportunities to explore. Visitors can wind between imposing rock walls, navigate narrow passages and scramble over rocks for a different perspective of the surrounding landscape. A closer look at some of those rocks reveals another piece of the area’s geological history. Vesicular basalt, commonly found throughout the Gorge, is dotted with small holes created by gas bubbles trapped in molten lava as it cooled and hardened. Millions of years later, those bubbles remain preserved in solid stone. It’s a small reminder of the Gorge’s more turbulent times. While Horsethief Butte’s geology is impressive, the surrounding landscape also holds deep cultural significance. For generations, Indigenous communities gathered along this stretch of the Columbia River to fish, trade and build connections. The river was an important center of life and commerce for Native peoples long before modern highways crossed the region. Nearby, at the Horsethief Lake section of Columbia Hills Historical State Park, visitors can see preserved examples of Indigenous rock art. The Temani Pesh-Wa display features petroglyphs and pictographs that were removed from their original locations in the 1950s, before rising waters behind The Dalles Dam submerged those sites. The rock art was eventually placed on public display in 2003, preserving an important connection to the people who lived along the Columbia River. Visitors can explore the relocated rock art display on their own during daylight hours from April through October. The park also offers guided tours to Tsagaglalal, commonly known as “She Who Watches,” one of the region’s most significant Indigenous rock images. Those tours are available by advance reservation on Fridays and Saturdays at 9 a.m. from April through October. Access to the site is restricted to guided tours to help protect the culturally significant artwork. Back at the butte, the experience is a little more hands-on. Although the hiking distances are short, the terrain can be uneven, with loose rocks and sections that require careful footing. “Wear shoes that have a good grip. Take a walking stick if you can,” Sieglein advised. “Be careful on the loose rocks, but it’s nothing too crazy.” The scenery here is a dramatic departure from the evergreen forests and lush landscapes farther west in the Gorge. Instead, visitors are surrounded by open skies, dry hillsides and rugged basalt cliffs. It’s a different kind of Pacific Northwest beauty, and one that Sieglein says shouldn’t be overlooked. For her, the appeal goes beyond the geology or the views. “It renews your soul. It really does,” she said. Sometimes, a change of scenery is all you need. Reprinted, with respect, from KGW8
The Rocks Tell An Explosive Story
If you drive up the Klickitat River Canyon, you might pass a strange, colorful rock outcrop without realizing you’re looking at the scene of an ancient volcanic explosion. At first glance, it looks like a stacked sandwich of different rocks: a soft red layer on the bottom, a hard, overhanging brown to buff-colored middle layer, another soft, buff to pink-colored layer above that, and a thick cap of weathered basalt covering it all. But if you know how to read the rocks, this outcrop reveals a dramatic, step-by-step saga of fire, ash, and lava. The story begins with a large volcanic eruption—likely from the nearby Mt. Adams area. As the eruption blasted into the sky, a scorching, high-speed cloud of gas and incandescent ash—known as an ignimbrite or pyroclastic flow—came racing downslope along a shallow channel on the surface of a thick air-fall ash deposit from an earlier eruption. This avalanche of glowing ash was so hot that, as it roared down the shallow channel, it literally baked the soft ash layer underneath it, scorching it into a deep, rich red color. And as it finally settled, the flow was so hot that it fused its own ash particles into a tough, solid rock layer called welded tuff. As the fiery tuff hardened, lighter ash from the eruption drifted down from the sky, forming a softer, buff-colored layer of air-fall ash on top of the welded tuff. Finally, a thick stream of molten basalt lava from the eruption slowly crept downslope and poured over the upper layer of air-fall ash, capping the entire pile with a heavy layer of dark, solid rock that slightly baked the air-fall ash directly beneath it. This outcrop is special because it’s rare to find a single hillside outcrop that preserves every stage of an eruption so perfectly. In just one glance, this roadside outcrop captures the full timeline: from the initial superheated pyroclastic flow, to the gently falling air-fall ash, to the final cooling lava field. And the outcrop is a striking example of how the rocks can tell a story if you take the time to read it. By Lloyd DeKay (editing assist by Gemini)
Reading Stories Written in the Rocks
Every geologist has a secret superpower: the ability to look at a cliffside or a pile of river rocks and read the ancient stories locked inside. But an even greater superpower is translating those stories into a tale so vivid that anyone can picture the world as it once was. On a recent field trip up the Klickitat River Canyon, we stopped in front of a roadside outcrop that holds a chapter of a truly cataclysmic story. Where the Ice Age Floods Ran Backward – Imagine a wall of water hundreds of feet high, thick with mud and carrying boulder-sized rocks, roaring down the Columbia River Gorge. As this massive torrent surged toward the Pacific, the deluge was so vast that it couldn’t fit within the main river channel. Instead, water violently backed up into every side canyon it passed—including the Klickitat River Canyon. Looking closely at this roadside cliff, you can see the clear evidence of this chaos: Layer 1: The Surge. A massive 6- to 10-foot-thick layer of jumbled mud and rounded boulders—debris carried by Ice Age Floods that slammed into the canyon as they surged up from the mainstem of the Columbia River. Layer 2: The Settling. A smooth, 1- to 2-foot layer of fine mud on top, settling out as the flood temporarily crested, possibly for days, as the flood waters continued to rampage through the Columbia Gorge, before the flood waters slowly drained back into the main Columbia River channel. Layer 3: The Repeat Performance. A second matching set of thick boulders and fine silt directly above the first—proof that this monstrous event happened more than once. Right at the top sits a third layer of mixed angular and rounded rock that could also mark a third flood that carried some much more local debris, or perhaps it marks a volcanic mudflow (a lahar) that raged down-canyon from nearby Mt. Adams sometime after the previous floods subsided. Unlocking the Flood Depth – How deep were these apocalyptic floods? The rocks hold some clues: 315 Feet Deep in the Canyon: The roadside outcrop described above sits at an elevation of ~330 feet—over 300 feet above the current bed of the Columbia River at the mouth of the Klickitat. To deposit these large boulders, the rampaging floodwaters had to run up the canyon to that elevation, at least 315 feet above the base of the main Columbia River at the Klickitat mouth. Over 600 Vertical Feet and 8.7 Miles Further Upriver: 8.7 miles further up the Klickitat, we spotted similar flood deposits sitting at an elevation of 630 feet, implying that that main flood flowing through the Columbia was at least 615 feet deep. A Record of an 800+Foot Deep Flood: Immediately across the Columbia River at Rowena Crest, a visible “trimline” scoured into the landscape suggests the absolute largest floods crested there at 840 feet in elevation—implying an astounding flood depth of roughly 825 feet. Because the narrow walls of the Klickitat Canyon created friction and drag against the invading water, the back-flooding in the side canyons like the Klickitat likely couldn’t reach the full height of the main river’s crest. But even considering that drag, standing next to these roadcuts and looking up, it is humbling to realize that thousands of years ago, you would have been standing hundreds of feet beneath a churning flood of mud-saturated water and transported rocks, some of them possibly from as far away as western Canada. Article by Lloyd DeKay (editing assist by Gemini )
Celebration Park – Home of Melon Gravel
17,000 years ago, a massive Ice Age lake – now called Lake Bonneville – filled a large portion of present-day Utah. As temperatures changed, the influx of ice melt caused the lake level to rise. In addition, the Bear River, once a tributary of the Snake, was diverted by volcanic activity back into Lake Bonneville. These factors ultimately led to the breaching of a sedimentary rock dam at Red Rocks Pass, Idaho. There was only one ice-age Bonneville Flood because Lake Bonneville broke through a rock dam, unlike the Missoula Floods whose glacial ice dam repeatedly dammed Glacial Lake Missoula, then broke and rebuilt. 1,100 cubic miles of Lake Bonneville water rushed through the Snake River Canyon, and it took only six weeks for Lake Bonneville to empty the equivalent volume of modern-day Lake Michigan. The Great Salt Lake we know today is a remnant of Lake Bonneville, but at one tenth the size, it is a mere puddle compared to what the lake used to be. The power of this catastrophic flood widened canyons as the force of the water pulled huge chunks of basalt off the cliffs and tumbled them around, smoothing their jagged edges along the way. As the canyon width narrowed, the force and velocity of the flood increased. Wherever the canyons widened, the flood lost force and velocity, the waters slowed and began dropping its bedload – in this case, giant tumbled basalt boulders instead of your typical river gravel. These flood-rounded boulders, named melon gravel due to their distinct shape, are scattered over vast areas of land. The rocks’ unique outlines and smooth surfaces caught the eye of Native American tribes in the area, who have used them as canvases for petroglyphs for thousands of years. Visitors can see the medium sized flood deposits just outside the visitor center, or hike upriver to see gigantic melon gravel the size of heavy-duty trucks. Celebration Park is located in the Snake River Canyon, approximately 23 miles south of Nampa, Idaho. It is home to an enormous melon gravel field deposited by the Bonneville Flood.
Glacial erratics of the Puget Lowland
Strewn among the forests of the Puget Lowland are an impressive array of Glacial Erratics. Although technically erratics include small pebbles and even sand grains in till, people tend to get the most excited by really big erratics- those the size of a house or building. Whatever their size, glacial erratics often reveal the direction of the ice flow that ripped them from their source region and deposited them at their resting place. Erratics can also help determine the thickness of the ice sheet that deposited them. In the Seattle area, it is relatively straightforward to determine the provenance of erratics containing quartzite, as that rock can not be found anywhere in the Olympics, the Cascades, or in the native bedrock of the Puget Lowland. Quartzite, which is durable and resistant to weathering, is commonly found in river valleys of central British Columbia and in the glacial tills of the Puget Lowland. However, granodiorite erratics found in the lowland and on the slopes of the Olympics and Cascades can be more difficult to decipher. The granodiorite in these erratics is chemically similar to rock bodies both in the British Columbia Coast Mountains and in the Cascades. In the mountains east of Bellingham, erratics found at 5,000 ft of elevation imply that the thickness of the Puget Lobe of the Cordilleran Ice sheet was at least 5,000 ft thick at that location. Maps showing the thickness of the Cordilleran Ice Sheet at various places in Western Washington are drawn, in part, by looking at the depositional altitude of erratics on ridges around the region. The two most massive erratics in the Puget Lowland are composed of Greenschist metamorphic rock. One of the giant erratics of Western Washington hides in the forest in Saratoga Woods Park on Whidbey Island. The Waterman erratic is 38ft high and has a circumference of 135 ft. Analysis of the rock shows that it is composed of Greenschist, a rock containing the low grade metamorphic minerals Chlorite and Epidote. The Greenschist chemically matches the rock of Mt. Erie, a prominent Roche Moutonée found 40 miles to the north on Fidalgo Island. An even larger erratic can be seen in a suburban neighborhood near Everett. The Lake Stevens erratic, 34 ft tall with a circumference of 210 ft, is considered the largest erratic in the Northwest, and possibly the largest erratic in the United States. This erratic is also composed of a Greenschist, although chemical analysis cannot give us a definitive origin for the big rock. There is similar Greenschist on the northern tip of Whidbey Island at Deception Pass, around Mt. Shuksan in the North Cascades, and also up the Fraser River in British Columbia. Article by Dale Lehman
DNR Releases Stunning Dry Falls Visualization
DNR’s Daniel Coe collaborating with Joel Gombiner has produced a stunning arial oblique visualization and poster showing incredible detail of the Dry Falls geologic complex. The DNR webpage announcing the release also shows additional materials like sliders illustrating differences in image capture resolution and grayscale vs. color representation, as well as Bretz’s scaled line drawing sketch comparing the Dry Falls Complex to Niagara Falls.
“The Next Big One” – NOVA|PBS Short Video
NOVA|PBS is sharing a short 5:16 min) video, THE NEXT “BIG ONE” – The Next Big Earthquake Could Sink Parts of the Pacific Northwest. It contains a brief explanation of the potential timing, causes, and some effects of the impending and widely-feared next Cascadia Earthquake Zone rupture. It’s worth a watch for most anyone in the PacNW.
Moses Coulee: An Ice Age Enigma
Washington state is famous for its dramatic landscapes, many carved by the immense power of the Ice Age Floods. We know the stories of the Grand Coulee, Palouse Canyon, and the Potholes. But tucked away in north-central Washington, cutting a path from northeast to southwest across the Okanagan Plateau, lies Moses Coulee – perhaps the most mysterious of them all. Unlike its famous cousins, Moses Coulee doesn’t quite fit the standard narrative. Its head seemingly emerges from beneath the Wisconsin Withrow Moraine, and its very formation presents a fascinating puzzle for geologists. Flood Theories and Questions: An Enigma The Grand Coulees (Upper and Lower) are widely believed to have been carved by the spectacular Missoula Floods. These colossal deluges were unleashed when the Okanagan Lobe of the Cordilleran Ice Sheet blocked the Columbia River, redirecting massive amounts of water southward. For Moses Coulee, it’s not so clear-cut. While cataract retreat due to massive floodwaters is generally assumed, most theories suggest the Okanagan Lobe effectively blocked the Missoula Floods from entering Moses Coulee. So, what carved this impressive landscape? Enter J. Harlan Bretz, the pioneering geologist who first championed the idea of colossal floods shaping the Pacific Northwest. Bretz observed a distinct wide bench within Moses Coulee, high above its floor. This led him to speculate about two distinct periods of glacial floods: An older, pre-Wisconsin “Spokane Flood” that initially carved Moses Coulee. A later Wisconsin period flood (what we now call the Missoula Floods) that deepened the coulee floor. Interestingly, current speculation suggests the Upper Grand Coulee might also owe its primary formation to these earlier “Spokane Floods,” with the Lower Grand Coulee being a product of the later Missoula Floods. It seems the story of Washington’s coulees is far more layered than once thought! Beyond Glacial Lakes: A Subglacial Hypothesis But wait, there’s another fascinating idea. Some investigators propose that Moses Coulee wasn’t carved by the well-known Missoula or Columbia glacial lake outbursts at all. Instead, they suggest outbreak floods from under the ice sheet itself. Joel Gombiner and Jerome Lesemann have explored this idea, suggesting that the immense pressure of the overlying ice lobe could have forced subglacial meltwater to flow uphill over topographic highs. This water would then have exited from under the ice, becoming the powerful floodwaters that sculpted Moses Coulee. Imagine that — floods erupting from beneath a massive glacier! Explore the Mystery Yourself The interplay between the Withrow Moraine and the unique features of Moses Coulee makes this a truly captivating area for exploration, especially for those intrigued by the raw power of ancient ice and water. To truly enhance your visit to this less-traveled gem, we highly recommend: Watching several of Nick Zentner’s insightful videos where he dives deep into these Moses Coulee questions. His engaging explanations bring the geology to life! Examining J. Harlan Bretz’s original field notes, meticulously organized in geolocated Google Maps by Glenn Cruickshank. It’s like stepping back in time with the pioneering geologist himself. Moses Coulee is more than just a landscape; it’s an ongoing geological debate etched into the earth. Are you ready to explore this remarkable natural mystery? AI-assisted article by Lloyd DeKay – Columbia River Gorge Chapter
A New Class of Plate Tectonics – Lithospheric Dripping
Crinkles and divots in the surface of Earth on Türkiye’s Central Anatolian Plateau are the smoking gun for a newly discovered class of plate tectonics. Beneath a depression called the Konya Basin, Earth’s crust is slowly dripping deeper into the planetary interior, a process that is gradually shaping the surface geology of not just the basin, but the plateau that surrounds it. It’s called lithospheric dripping, a phenomenon that has only recently been discovered here on Earth, and geologists are still figuring out the different ways it manifests. When the lower portion of Earth’s rocky crust is heated to a certain temperature, it starts to go a little gooey. Then, like honey or syrup, it slowly oozes downward – a bit like a pitch drop experiment, but much bigger and slower. As this drop descends, it pulls the planetary crust down with it. This creates a depression, or basin. Then, when the drop detaches into the mantle, the surface rebounds, bulging upwards, with a widespread effect. The Central Anatolian Plateau is known to be uplifting over time. Previous research suggests that it has gained around a kilometer (0.6 miles) in altitude over the past 10 million years thanks to the release of a crusty drip. But then there’s the Konya Basin, which is subsiding downwards at a rate of around 20 millimeters (0.8 inches) per year. That doesn’t sound like much, but a sinking patch of ground in a region that is rising upwards warrants further investigation. The broader region of the plateau is in the throes of the rebound phase of the lithospheric drip process, after having dropped its gooey molten load into the mantle. The Konya Basin? That’s a smaller, second drip forming. “As the lithosphere thickened and dripped below the region, it formed a basin at the surface that later sprang up when the weight below broke off and sank into the deeper depths of the mantle,” says Earth scientist Russell Pysklywec of the University of Toronto. “We now see the process is not a one-time tectonic event and that the initial drip seems to have spawned subsequent daughter events elsewhere in the region, resulting in the curious rapid subsidence of the Konya Basin within the continuously rising plateau of Türkiye.” Excerpt from a Science Alert article By Michelle Starr