The Great Missoula Floods

By Alice Winship

Frenchman Coulee

Chorus: You can’t run and you can’t hide
             A wall of water five trees high
             The rumble grows and fills the sky
             From the Great Missoula Flood
             The water rips the rock like clay
             Soil and bedrock stripped away
             A maze of scabland seen today
             From the Great Missoula Floods

The Pleistocene when the ice sheets flowed
Made a big lake that growed and growed
Each time an ice dam plugged the gap
The river flow was trapped
Glacial Lake Missoula was deep
Up in Montana where the valleys are steep
When ice dams broke, the floods unfurled
The biggest in the world


The water crashes across the plain
Columbia’s full and cannot drain
Her gorge is ripped up the mountainside
The flood is deep and wide
Erratic boulders strewn about
A whirling vortex plucks rock out
Basaltic columns ground to sand
The marks left on the land


The buttes and coulees are dry and brown
Meadowlark sings a song that trickles down
Green and gray is the twisted sage
The cliffs show bands of age
A kolk lake shines like a bright green jewel
Pothole waters are deep and cool
Rattlesnakes dream and the rabbits run
Rocks shimmer in the sun



Disasters are best viewed from a position of safety, and it’s hard to find a safer distance than the 12,000 to 15,000 years that separate us from the ice age floods that carved so much of the landscape of eastern Washington.

An ice sheet dammed the Clark Fork in Montana, creating a huge lake, whose waters swept over eastern Washington and down the Columbia when the ice dam broke. This happened many times, perhaps forty or more.

The rumble of the flood waters approaching at 50 miles an hour would have been heard for half an hour before the water arrived, preceded by a blast of displaced air with the power of a bomb. The wall of water was 500 feet high at the outset, spreading out over the Columbia Plateau, but rising again to 500 feet when constricted by the Columbia River Gorge. The water was over 300 feet deep when it went over Dry Falls in Grand Coulee. As the flood plunged over the 400-foot drop of this 3-mile wide cliff, it would not have looked like a waterfall, only a ripple on the surface of the sheet of water. In the Columbia River Gorge, the water reached depths of over 1000 feet, and flooded much of the Willamette River Valley, at a depth of 400 feet where Portland now stands.

The floods left dry coulees and channeled scablands over large areas of Eastern Washington, and carved out the Columbia River Gorge from a V-shaped valley to a U-shaped valley, with steep cliffs and waterfalls that plunge into space.

There probably were people here at the time, although all traces of human presence were washed away by the floods. Most people would have been living on low ground, near the rivers, and only those on the highest ground could have survived.

Some notes about words used in the song:
Erratic boulders – Erratics are rocks which differ from the type of rock that usually occurs in the location where they are found. Those in the area of the ice age floods were first picked up by the ice sheet, then rafted inside huge chunks of ice which subsequently melted. They range from gravel-size to larger than a house.

Kolk is a word of Dutch and German origin. The Dutch observed that when a dike broke, kolks could hoist large blocks of rip-rap from the dike. An underwater vortex is created when water passes an obstacle at high velocity. This creates a twisting column of water like an underwater tornado, which can lift rocks and whirl them. A circular pothole is dug out both by removal of rock, and by the grinding action of the rocks trapped in the vortex. Potholes several feet across are often found along rivers, but the potholes formed by the ice age floods are huge, ranging from house-size to basins several miles long. Some of the potholes in the Channeled Scablands are dry, but others have filled with seep water to form kolk lakes, fringed with green wetlands.

The bedrock in Eastern Washington is columnar basalt, formed by lava flows which repeatedly covered the entire Columbia Basin. When basalt cools, it forms five-sided columns, usually a foot or more across. These
naturally occurring joints in the rock allowed the kolks of the ice age floods to pluck out huge columns of basalt. Much of this rock was ground to a flour-like powder, which either washed out to sea, or blew back as loess to add to the rich farmlands of eastern Washington. The lava flows show as layers in the cliff walls of coulees, a French Canadian term for a dry channel. Some are huge, like Grand Coulee; some are a maze of channels.

Scabland originally was a local term meaning ‘land too rocky to farm’. It’s similar to ‘badlands’. Geologist J. Harlan Bretz called them the Channeled Scablands to describe the unique formations he was observing, that could only have been formed by a massive flood, although his colleagues sneered at the idea for several decades. Geologists now like the term, because it describes something that happened so recently, in terms of geologic time, that it hasn’t had time to heal.

The farm where I grew up in Eastern Washington is within sight of one of the most significant and dramatic areas of Channeled Scablands on the Columbia Plateau, called the Drumheller Channels, although the locals just call it Potholes. About a mile down the road from our house, the farmland ends, and a maze of rocks, lakes, coulees, buttes, and strange-shaped hills begins. About five miles down the road is the Drumheller Channels National Natural Landmark, named after Drumheller Ranch which used to be there. It’s also the Columbia National Wildlife Refuge, known for small mammals, reptiles, and many species of birds. Upper Goose Lake was our favorite swimming hole when I was in high school.


  • Written by: Alice Winship
  • Arranged: Alex Sturbaum
    • Helen Gilbert: lead vocal
    • Laura Bassett: harmony vocal
    • Alex Sturbaum: banjo, guitar, harmony vocal
    • Wendy Joseph: harmony vocal

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