On June 5, 1976, a newly constructed earthen dam on the Teton River, in eastern Idaho, catastrophically failed. The dam was built by the US government and was allowed to start filling the previous November, and by June, the lake had reached capacity. At 7:30 in the morning a leak began to appear on the face of the dam. The workers at the site tried to seal the leak with heavy bulldozers during the course of the morning, but the leak steadily grew over the course of the following hours. The workers, realizing the danger, withdrew from the area at the base of the dam.
As the flow of water from the northern end of the dam increased, it began to erode the sides of the dam where it was tied to the underlying rock base. At 11:15 AM the authorities warned downstream residents of the impending danger and order evacuation of several towns. Finally at 11:55, just over four hours after the problem started, the top of the dam crumbled and water flowed over the dam in increasing volume. The breach widened, and at the height of the flow over 2 million cubic feet of water poured over the dam every second. By 8 P.M. the lake had been drained and with serious damage to the area with many Idaho homes destroyed.
With this result of this catastrophe, eleven people died, thousands of cattle were lost, there was over $1 billion in property damage, many businesses were lost, and there was a dislocation of several small villages along the river plain. Much of the loss was covered by the US government and payments were made into the 1980’s. The Teton Flood lead to much stricter monitoring of earthen dams in the US, particularly when the federal government is involved. What remains today is a large portion of the dam, showing the breach and the subsequent diggings to examine what went wrong and how it could be avoided in the future. Now the Teton Flood Museum maintains details about the dam’s failure and the aftermath for the residents that live in the area. The museum also houses an auditorium with great acoustics. This is a place to see and enjoy the history of the area.