The Lake Bonneville Flood
An Epic North American Catastrophe
I was attending a conference this week in Utah, which drew my attention to the geology and history of the Great Salt Lake Basin, in which the cities of Salt Lake City, Ogden, and several others are situation. What is today a lovely city on flat ground was, in Abraham’s day, uner 3,700 feet of freshwater.
During the Ice Age, the Great Salt Lake Basin was completey full of water. The geologists refer to it as Lake Bonneville. However, in the 16th century, when Moses was a young man, Lake Bonneville had a catastrophe.
The Bonneville watershed was surrounded by mountains on all sides. But the lowest point of the rim of the bowl was the mountain range to the north, bordering modern Idaho. As the Ice Age was ending the precipitation was still high, and the glaciers began melting worldwide. Lake Bonneville filled up to the elevation of 5,200 feet above sea level. And then, it overflowed.
At Red Rock Pass, about 80 miles north of Ogden, the waters of Lake Bonneville spilled over the lip of the mountainous cup containing the entire lake. What followed was legendary. The flood released several thousand cubic miles of water into the Snake River of Idaho.
The waters pouring through the pass rapidly eroded it down by 500 feet, allowing the top 500 feet of a lake half the size of the state of Utah to suddenly flow into the Snake River Basin of Idaho. As it made its journey to the sea, the ensuing flood carved out the Snake River Badlands, as well as Hells Canyon along the Snake River. The flood released on the order of several thousand cubic kilometers of water and did much scoured out the Snake River Canyon and created features like Shoshone Falls and the “watermelon” boulders near Hagerman.
The deluge then flowed into the Columbia River and finally came to the sea. After the end of the Ice Age, the climate of the American West dried out, and lake Bonneville began slowly receding, century by century, until all the remained is the body of water that we know today as The Great Salt Lake.
