IECA Pulse: Unearthing Earth's Epic Past: The Missoula Floods of the Channeled Scabland

By Heather Gravning posted Sep 27, 2023 11:44 AM


The stage is set, the anticipation palpable, as we prepare to embark on a journey back in time, to an era when the world was a vastly different place. Imagine the Pacific Northwest, a land shaped not just by the steady hands of time but by cataclysmic events that defy imagination. This year at our annual conference, we are honored to present a keynote session that promises to leave you in awe: "The Ice-Age Missoula Floods of the Channeled Scabland - Two Stories of Science," presented by Geologist Jim O'Connor of the U.S. Geological Survey. 

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When: Monday, February 26th | 8:30 AM - 9:30 AM

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Scenic photo from above of Dry Falls at Grand Coulee, Washington, 
400 ft tall, carved by the ice-age Missoula Floods. Photograph by Bruce Bjornstad
View this video animation of the Dry Falls

A Geological Epic Unveiled

The Channeled Scabland of the U.S. Pacific Northwest stands as hallowed ground for unraveling the mysteries of ice-age megafloods. The stories etched in its landscape are the stuff of geological legend, and at the heart of this epic tale are the Missoula floods.

Around 15,000-20,000 years ago, as the last ice age began to wane, a massive ice lobe crept southward from the Rocky Mountains in Canada. This icy behemoth blocked the path of the Clark Fork River in northern Idaho and western Montana, creating a colossal ice-dammed lake known to geologists as Glacial Lake Missoula. Picture a lake more than 650 meters deep, containing a staggering 2500 cubic kilometers of water – that's twenty times the size of Puget Sound!

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But nature, as always, has her own plans. The ice dam holding back this colossal reservoir repeatedly ruptured and reformed, triggering a series of cataclysmic outbursts. With a force that's difficult to fathom, these floods sent torrents of water hurtling down the Spokane Valley, across eastern Washington, and down the Columbia River.

The results were nothing short of spectacular. The floodwaters, in some areas over 1000 feet deep, raced at speeds of up to 100 feet per second, lifting boulders the size of automobiles and tumbling them downstream. In an instant, the face of the Pacific Northwest was transformed. Rivers were rerouted, valleys backfilled with silt and clay, and the Channeled Scablands carved into existence. Sand and gravel bars hundreds of feet high were deposited, and the iconic Columbia River Gorge took shape.

Science Transformed by Cataclysm

But the Missoula floods didn't just reshape the land; they also revolutionized the science of geology. In a time when the prevailing wisdom held that Earth's features were shaped exclusively by slow, gradual processes taking millions of years, these floods presented a challenge. Early geologist J Harlen Bretz boldly proposed the idea of these cataclysmic floods, sparking a heated debate that spanned decades.

This debate, with its twists and turns, ultimately led to a transformative shift in our understanding of Earth's history. Bretz's perseverance prevailed, and today, we recognize such cataclysms as integral to the story of our planet's evolution.

Yet, the story doesn't end there. Ongoing research into the landscapes shaped by these megafloods continues to reveal surprising findings, pushing the boundaries of our knowledge about one of the most significant events in Earth's history.

Join us this February as we delve deep into this remarkable chapter of our planet's past. Jim O'Connor, a distinguished geologist from the U.S. Geological Survey, will be our guide on this extraordinary journey. Together, we will unravel the mysteries of the Missoula floods and the Channeled Scabland, celebrating the wonder of our world's geological history.

Don't miss this opportunity to witness science and nature converge in a symphony of discovery. The keynote session promises to be an intellectual and awe-inspiring experience that will leave you with a newfound appreciation for the power of Earth's past.

Registration is open, and we invite everyone to join us from February 25-28, 2024. Be sure to book your room early at The Davenport Grand Hotel due to limited availability! 

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Let's make this conference a celebration of knowledge, curiosity, and the breathtaking stories hidden within the Earth's rocky layers.

See you there!

Jacob Burkey

Professional Development Committee