Ice Age Floods Trail | TheFencePost.com

Ice Age Floods Trail

Candy Moulton
Encampment, Wyo.

One of the newest national trails is the Ice Age Floods Trail, approved in 2008 as part of a Congressional lands bill. Some may wonder why the heck would anybody want to follow a trail of ice, and may especially question my sanity given the stage of current weather conditions (a Canadian cold front is bearing down on Wyoming and Colorado as I write this.) 

To be honest, I’d never heard of the Ice Age Floods Trail prior to the Congressional action. But I have traveled much of it both before and after that declaration.

The trail crosses the area that was significantly impacted by flooding as part of the last Ice Age – a period roughly 12,000 to 18,000 years ago. During that time a lobe of ice that was part of the Cordilleran ice sheet flowed south from Canada into what is now western Montana and the Pacific Northwest. That ice began to melt and formed a huge lake – known as glacial Lake Missoula – that was held back by a dam created from a section of the flowing ice itself.

When the icy dam burst the water flooded the Columbia Basin across parts of what are now Montana, Idaho, Washington and Oregon. This flooding, that happened every 40 to 140 years or so, scoured the land forming coulees, basins, flood bars and gorges.  

Lake Missoula once rivaled today’s Great Lakes in size, but as the glacial ice receded, the naturally formed dam that had blocked what became the Clark Fork River in northwestern Montana eventually disappeared and with it the cycle of flooding. No longer scoured every few dozen years, the land filled in, vegetation regenerated, and ultimately became home to Columbia Basin tribes and later to Euro-Americans who came as explorers and for land or gold.

The Ice Age Floods National Geologic Trail is not a trail in the sense that it represents the movement of people or even animals on the ground, but rather one that reflects the passage of the water as it flowed from Lake Missoula across the Pacific Northwest to the Pacific Ocean.

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Geologists have several names for the most recent Ice Age Floods in the Pacific Northwest: the Missoula Floods, the Spokane Floods, Bretz Floods and Ice Age Floods. Regardless of the name associated with the floods, the effects of massive water flowing across the region are undeniable because of the evidence left behind including huge boulders where there shouldn’t be any such objects, rippled land forms, deep canyons or coulees and other tangible reminders of the Ice Age.

Today when you travel across the region, you will see evidence of the flooding and the impact of the melting of the ice pack. Glacier National Park in Montana has remnants of the glaciers that formed the ice pack responsible for the natural barricade maintain the cycle of freezing and growing, thawing and diminishing. Going-to-the-Sun road between St. Mary on the east side of the park and West Glacier, gives you a view of the rugged terrain. During the summer season you can hike atop the divide at Logan Pass, where you will not only be able to experience glaciers, but also view a variety of wildlife from Rocky Mountain goats to small mammals. For a completely different experience you can walk along the Trail of Cedars through the deep forest on the west side of Glacier National Park.

Missoula, Montana, was named by the Salish Indians for the word meaning “near the cold, chilling waters,” no doubt a reference to the Ice Age body of water. C.P. Higgins and Francis Worden started the first trading post in the area calling it Hell Gate. Almost certainly during the last Ice Age, this was near the site where the waters of Lake Missoula formed behind the natural ice dam, only to burst through and flood the Pacific Northwest.

Today’s Missoula has Irish and German festivals, the Missoula Children’s Theater, and other events to experience. The icy waters of Lake Missoula would have flowed along what is now the Clark Fork River valley to Pend Oreille Lake and Sandpoint, Idaho, a region you can explore by following Montana highway 200.

One of the most obvious remnants of the great Ice Age flooding is visible on the Columbia River at Grand Coulee, Washington. Here you can view a 400-foot-high cataract called Dry Falls located 20 miles southwest of Grand Coulee Dam. This is the only place along this Flood Trails route where there is an interpretive center focused on the Ice Age Floods, The J. Harlen Bretz Visitor Center at Sun Lakes-Dry Falls Interpretive Center (named for the geologist who first recognized and documented the evidence for the Ice Age floods).

I’ve been in this region more than once and liked to drive south from Spokane on U.S. 195 through Rosalia and Steptoe to Colfax. Here you can take highway 26 southwest to highway 260 and then to U.S. 395 to the Tri-Cities.

Two National Natural Landmarks, Wallula Gap located west of Walla Walla, Wash., and the Drumheller Channels, near Othello, Wash., are the direct result – and two of the better tangible places to view evidence – of the floods. As J. Harlen Bretz, the geologist who initially recognized and documented the evidence for these Pleistocene era floods, wrote, “Drumheller is the most spectacular tract of butte and basin scabland on the plateau. It is an almost unbelievable labyrinth of channels, rock basins, and small abandoned cataracts.”

One effect of the flooding is the rich soil deposited across the region and the climate in Washington is conducive to the growing of vineyards, meaning that although you may know about Washington apples, you will also find plenty of opportunity to visit wineries as you travel from Tri-Cities to Vancouver.

At Dallesport, Wash., you can take US 197 and cross the Columbia to The Dalles, where you should visit the Columbia Gorge Discovery Center, which has some interpretation related to the Ice Age Floods and their impact on the Columbia River Gorge.

One of the newest national trails is the Ice Age Floods Trail, approved in 2008 as part of a Congressional lands bill. Some may wonder why the heck would anybody want to follow a trail of ice, and may especially question my sanity given the stage of current weather conditions (a Canadian cold front is bearing down on Wyoming and Colorado as I write this.) 

To be honest, I’d never heard of the Ice Age Floods Trail prior to the Congressional action. But I have traveled much of it both before and after that declaration.

The trail crosses the area that was significantly impacted by flooding as part of the last Ice Age – a period roughly 12,000 to 18,000 years ago. During that time a lobe of ice that was part of the Cordilleran ice sheet flowed south from Canada into what is now western Montana and the Pacific Northwest. That ice began to melt and formed a huge lake – known as glacial Lake Missoula – that was held back by a dam created from a section of the flowing ice itself.

When the icy dam burst the water flooded the Columbia Basin across parts of what are now Montana, Idaho, Washington and Oregon. This flooding, that happened every 40 to 140 years or so, scoured the land forming coulees, basins, flood bars and gorges.  

Lake Missoula once rivaled today’s Great Lakes in size, but as the glacial ice receded, the naturally formed dam that had blocked what became the Clark Fork River in northwestern Montana eventually disappeared and with it the cycle of flooding. No longer scoured every few dozen years, the land filled in, vegetation regenerated, and ultimately became home to Columbia Basin tribes and later to Euro-Americans who came as explorers and for land or gold.

The Ice Age Floods National Geologic Trail is not a trail in the sense that it represents the movement of people or even animals on the ground, but rather one that reflects the passage of the water as it flowed from Lake Missoula across the Pacific Northwest to the Pacific Ocean.

Geologists have several names for the most recent Ice Age Floods in the Pacific Northwest: the Missoula Floods, the Spokane Floods, Bretz Floods and Ice Age Floods. Regardless of the name associated with the floods, the effects of massive water flowing across the region are undeniable because of the evidence left behind including huge boulders where there shouldn’t be any such objects, rippled land forms, deep canyons or coulees and other tangible reminders of the Ice Age.

Today when you travel across the region, you will see evidence of the flooding and the impact of the melting of the ice pack. Glacier National Park in Montana has remnants of the glaciers that formed the ice pack responsible for the natural barricade maintain the cycle of freezing and growing, thawing and diminishing. Going-to-the-Sun road between St. Mary on the east side of the park and West Glacier, gives you a view of the rugged terrain. During the summer season you can hike atop the divide at Logan Pass, where you will not only be able to experience glaciers, but also view a variety of wildlife from Rocky Mountain goats to small mammals. For a completely different experience you can walk along the Trail of Cedars through the deep forest on the west side of Glacier National Park.

Missoula, Montana, was named by the Salish Indians for the word meaning “near the cold, chilling waters,” no doubt a reference to the Ice Age body of water. C.P. Higgins and Francis Worden started the first trading post in the area calling it Hell Gate. Almost certainly during the last Ice Age, this was near the site where the waters of Lake Missoula formed behind the natural ice dam, only to burst through and flood the Pacific Northwest.

Today’s Missoula has Irish and German festivals, the Missoula Children’s Theater, and other events to experience. The icy waters of Lake Missoula would have flowed along what is now the Clark Fork River valley to Pend Oreille Lake and Sandpoint, Idaho, a region you can explore by following Montana highway 200.

One of the most obvious remnants of the great Ice Age flooding is visible on the Columbia River at Grand Coulee, Washington. Here you can view a 400-foot-high cataract called Dry Falls located 20 miles southwest of Grand Coulee Dam. This is the only place along this Flood Trails route where there is an interpretive center focused on the Ice Age Floods, The J. Harlen Bretz Visitor Center at Sun Lakes-Dry Falls Interpretive Center (named for the geologist who first recognized and documented the evidence for the Ice Age floods).

I’ve been in this region more than once and liked to drive south from Spokane on U.S. 195 through Rosalia and Steptoe to Colfax. Here you can take highway 26 southwest to highway 260 and then to U.S. 395 to the Tri-Cities.

Two National Natural Landmarks, Wallula Gap located west of Walla Walla, Wash., and the Drumheller Channels, near Othello, Wash., are the direct result – and two of the better tangible places to view evidence – of the floods. As J. Harlen Bretz, the geologist who initially recognized and documented the evidence for these Pleistocene era floods, wrote, “Drumheller is the most spectacular tract of butte and basin scabland on the plateau. It is an almost unbelievable labyrinth of channels, rock basins, and small abandoned cataracts.”

One effect of the flooding is the rich soil deposited across the region and the climate in Washington is conducive to the growing of vineyards, meaning that although you may know about Washington apples, you will also find plenty of opportunity to visit wineries as you travel from Tri-Cities to Vancouver.

At Dallesport, Wash., you can take US 197 and cross the Columbia to The Dalles, where you should visit the Columbia Gorge Discovery Center, which has some interpretation related to the Ice Age Floods and their impact on the Columbia River Gorge.