My Life Travel and Adventure: On the road to Yellowstone Lake

Buffalo Bill Dam

On my way to Yellowstone Lake I stopped by the Buffalo Bill dam which straddles the Shoshone River and Rattlesnake Mountain. Like Wyoming's Wind River Canyon, Shoshone Canyon cuts directly across Rattlesnake Mountain. About 3 million years ago the Shoshone River flowed across a flat plain under which the deformed beds of Rattlesnake Mountain rested. Then the earth started to uplift and the river rapidly cut into, and eroded, the soft layers of limestone and sandstone that make up Rattlesnake Mountain. The sedimentary sandstone and limestone rocks were originally deposited 205 to 570 million years ago, on the beaches and near shore waters of a large, sub-tropical sea. About 60 million years ago, when the Rocky Mountains were born, compressive forces deep underground in the earth's crust started to deform and fold the layers that now make up Rattlesnake Mountain.

Compressive forces are forces that are parallel to the earth's surface as opposed to upward forces which are at right angles or perpendicular to the earth's surface. Compressive forces often fold layers of rock and cause them to buckle upwards.

Buffalo Bill Dam and Visitor Center

Earthquake Fault

At the north end of the dam, behind the visitor's center and the highway, is a major fault in the earth's surface. Note how the rocks to the right of the photo are pink and gray. They look like someone squeezed them from a giant toothpaste tube. The layers are almost fluid and do not follow smooth planes like the tan and brown, limestones and sandstones, to the left of the photo.

The pink and gray rocks were deposited over two billion years ago! They were buried so deeply in the earth's surface that heat and tremendous pressure caused them to flow like toothpaste.
Faults are cracks that form in the earth's crust when rocks start to buckle or uplift. Rocks of vastly different ages can move past each other when a fault forms. At Buffalo Bill Dam I saw rocks that were two billion years old sitting next to rocks that were only 205 to 570 million year old because they had moved, relative to each other, along an earthquake fault. That fault formed when the Rocky Mountains were born, 60 million years ago.

Construction of the Buffalo Bill dam started on October 19th, 1905. It was the tallest (325 feet) arch style dam in the world at that time. Originally it was called the Shoshone River dam but was renamed to Buffalo Bill Dam in 1946. Irrigation for farmers and flood control were the two reasons for building the dam. In 1919 an electricity generating plant was added and today it powers several nearby towns. On January 15th, 1910 the final bucket of concrete was poured on the dam. The project was completed for just $929,658.00. To date, over 350 million dollars worth of crops have grown in the Shoshone Valley, as a result of the Buffalo Bill Dam. In addition, the hydroelectric plant at the dam generates 5.5 megawatts of pollution free electricity, and has been in operation for over 80 years.

Dam Modification Project

The dam was recently heightened by 25 feet which increased the capacity of the reservoir by 60%. The dam is now 350 feet tall, 200 feet long and the reservoir holds 646,500 acre feet of water. One acre foot of water is enough water to cover one acre of land to a height of one foot. You could flood a small city with the water behind the Buffalo Bill Dam.

New and old rock layers

When I read the words I have written they sometimes sound like an Earth Science 101 text book. I do not mean them as an introduction to Geology but rather as a chronicle of history that I am able to extract from the rocks. The rocks have a story to tell and I am a good listener. Hopefully their tale will not put you to sleep.
Just before I entered the Shoshone River Canyon I came across a place called Colter's Hell. What drew my interest was the way the rocks were screaming to me. Look at the photo to your left. On the bottom the layers or beds of rock are at about a 45 degree angle. Above those inclined layers is another layer, but this one is horizontal. The rocks are saying that the angled beds were laid down first, then compressive forces pushed them until they were at 45 degrees. Next wind and water eroded them so they were flat on top or level to the horizon. Then more sediments and in this case, volcanic ash, were laid on top of them. The rocks are pleased that their voices have been heard.

The mountains and canyons I saw in southern Wyoming originated 350 million years ago in a warm, shallow sea. The Rocky Mountains were born just 50 million years ago and now I was seeing volcanic rock that was directly related to that birth. The reddish brown rocks that covered the tops of the mountains along the banks of the Shoshone River were created when volcanoes spewed forth ash and chunks of rock that mixed with mud and debris.

Volcanoes, wind and water create Hoodoos

The Absorka Mountains to the west were the main source of this rock that geologists call breccia. A combination of rock chunks, ash and often mud, breccia covers most of Yellowstone National Park and the surrounding land. It is soft; wind and water easily erode breccia. Over time water and then wind swept sand eroded the breccia deposits on top of the mountains into fantastic shapes that are called hoodoos.

Yellowstone Lake beckons in the distance

My first experience with the changes occurring in Yellowstone National Park was a 30 minute traffic jam on the East Entrance road. I was not dismayed though. For 30 years the roads in the Park and much of its infrastructure were neglected. Automobiles and tourists in general were seen as destructive forces that needed to be controlled for the benefit of the Park. The idea of banning cars from the Park was seriously discussed. The ideal situation would be to declare the entire park off limits to roads and humans but that was not feasible. Fortunately, after 30 years, a more tolerant and encompassing view has prevailed. The Yellowstone road network is receiving sorely needed repairs and rebuilding. When completed, the road network will be safer, easier to maintain and will meet the needs of modern tourists who ride in SUVs and motor homes, not horse drawn stage coaches or Model Ts.

For More Information:

Click on the underlined text below to read more about:
Yellowstone National Park Lodging and activities or call them at (307) 344-7311.
Official National Park Service, Yellowstone Park information or call them at (307) 344-2386.
Yellowstone National Park Association educational programs, printed guides and online store or call them at (307) 344-2293.


Reddish Brown rocks tower above the Shoshone River	Strange shapes adorn the mountain's peak


Serious road construction in Yellowstone National Park	Year old burnt stand of Lodgepole Pine


Canyon and Power House	Buffalo Bill Reservoir