Dry Falls, An Historical Geological Event

As seen from the Sun Lakes-Dry Falls Interpretive Center


In Dry Falls, Washington, lies the skeleton of one of the greatest floods in geologic history.  The sheer volume of water and power of this historical calamity dwarfs any of the falls currently on the planet and is worth of study by those interested in the geologic record of the Pacific Northwest.


Dry Falls is a 3.5-mile-long (5,600 m) rock face in central Washington State, on the opposite side of the Upper Grand Coulee from the Columbia River, and at the head of the Lower Grand Coulee.  According to the current geological thought, catastrophic flooding channeled water at speeds up to 60 miles per hour through the Upper Grand Coulee and over this 400-foot (120 m) precipice during the last ice age. It is estimated that the falls were five times the width of Niagara Falls with ten times the flow of all the current rivers in the world combined.


This is a representation of how Glacial Lake Missoula would have appeared twenty thousand years ago.


Nearly twenty thousand years ago, as glaciers marched southward through much of North America, an ice sheet dammed the Clark Fork River near Sandpoint, Idaho.  Consequently, a significant portion of western Montana flooded, forming the gigantic Glacial Lake Missoula.   It is estimated that this lake, at various times, contained 500 cubic miles of water.


Eventually, water in Glacial Lake Missoula rose high enough to float the ice dam until it gave way, and a portion of this cataclysmic flood ravaged much of Eastern Washington, with approximately a third of its volume overflowing what is now Dry Falls.  It is generally accepted that this process of ice-damming of the Clark Fork, refilling of Glacial Lake Missoula and subsequent flooding happened dozens, perhaps hundreds, of times during the last Ice Age.


This plaque provides current scientific thought pertaining to the periodic Ice Floods over Dry Falls.

copyright 99% Invisible


These sudden floods inundated parts of Idaho, Washington, and Oregon under hundreds of feet of water in just a few days. And, they greatly enlarged the Grand Coulee and Dry Falls localities in a short period of time.





Once the ice sheet obstructing the Columbia melted, the river returned to its normal course, leaving the Grand Coulee and Dry Falls as they appear today.  The massive cliff pictured above can be viewed from the Dry Falls Interpretive Center, part of Sun Lakes – Dry Falls State Park and located on Washington State Route 17 near Coulee City.  Admission is free, although a Discover Pass is required for parking.


The following links contain various, informative, videos that should prove useful in studying Dry Falls and the geologic history of the area:








A field trip to the Sun Lakes – Dry Falls State Park is certainly worth the effort, as the historical, geological and ecological significance of the event cannot be overstated.  For all ecology students, as well as students merely interested in the novelty of the area, a trip to Dry Falls is an appropriate homeschooling exercise!


Activities and amenities

Sun Lakes – Dry Falls State Park has 73,640 feet (22,450 m) of lake shoreline and offers fishing, swimming, boating, hiking, horse rentals, and a golf course. The campground includes access to the lake, a swimming pool, and a mini golf course.  The park is also home to Camp Delany, with eight 9-person cabins and a central meeting hall accommodating up to 120 people.  If alternate accommodations are needed, nearby Coulee City, Soap Lake, and Ephrata offer full-service motels and dining establishments!


As an adjunct to your homeschooling field trip, please consider any of the following publications.  You’ll find a wealth of information contained therein!


The Grand Coulee Of Washington And Dry Falls In Picture And Story by Joseph G. Macken

Vintage Copy Of The Grand Coulee Of Washington And Dry Falls In Picture And Story Softcover — Published by Time Publishing Company Copyright 1950

Glacial Lake Missoula and its Humongous Floods by David AltGlacial Lake Missoula and its Humongous Floods by David Alt

This book tells the gripping tale of a huge Ice Age lake that drained suddenly — not just once but repeatedly — and reshaped the landscape of the Northwest. The narrative follows the path of the floodwaters as they raged from western Montana across the Idaho Panhandle, then scoured through eastern Washington and down the Columbia Gorge to the Pacific Ocean. This is also the story of geologists grappling with scientific controversy–“of how personalities, pride, and prejudice sometimes superseded scientific evidence.”


Cataclysms on the Columbia: The Great Missoula Floods by John Eliot Allen, Marjorie Burns, and Scott Burns

Cataclysms on the Columbia tells two stories. One follows geological research that challenged the scientific paradigm of the early 20th century, and the other chronicles the result of that research: the discovery of powerful prehistoric floods that shaped the Pacific Northwest. The cataclysms at the end of the last Ice Age left a scabland of buttes, dry falls, and rocky gorges, but it took the detective work of geologist J Harlen Bretz to prove it to the world. His lifetime of research and unshakeable belief changed geology forever.


GigaFlood: The Largest of the Lake Missoula Floods In Northwest Oregon and Southwest Washington by Rick Thompson

Covering a brief history of Glacial Lake Missoula and the factors leading to its creation and dam-bursting flood, GigaFlood follows the path of the largest of the Lake Missoula Floods, as its 540 cubic miles of water, 40 cubic miles of ice, 50 cubic miles of rock, sediment and debris tore down the Columbia River Gorge at speeds up to 65 miles per hour, and traces the influx and exit channels in the areas north and south of the Columbia River as it overflowed the Portland/Vancouver area as well as the Clackamas, Tualatin Yamhill and Willamette valleys up to the 400 foot level.


I hope you have found this information useful!  Please leave any comments or suggestions below.  If you have questions, I would be happy to field them, as I respond to all feedback!  My email address is provided for your convenience.

All the best with your homeschooling activities!

Mitch Crim



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