“As I sit here and watch I can see it caving in. It is just coming apart, completely coming apart… my advice to people downstream that are living along the Teton River, get your belongings, get your belongings. Don’t push your luck. Look, look, there goes the whole side, there goes whole complete side of the north edge of the Teton Dam and the water is monumental – holy – great – what can I say? People downstream better get out…”
From this transcript of a live broadcast aired on Rexburg Idaho’s KRXK radio station one is jolted back 40 years to June 5, 1976, when correspondent Don Ellis watched as the U.S. Bureau of Reclamation’s nearly 75 year run of successful dam building crumbled before his very eyes. Years of panels, inquiries, investigations, and on-site excavations all worked to pinpoint the exact cause of the Teton Dam failure, to no definite end, but the hundreds of millions of dollars of property damage and 11 deaths attributed to the disaster remain undisputed. The story, from beginning to the tragic ending, can be found in the National Archives at Denver’s Record Group 115 Records of the Bureau of Reclamation holdings.
Construction of the dam had been authorized by Congress 12 years earlier on September 7, 1964. Planned on the Teton River, a tributary of Henry’s Fork of the Snake River in southeastern Idaho, the earth-filled embankment dam and reservoir were to be the main features of the Teton Basin Project, designed for flood control, power generation, and supplemental irrigation for nearby farmland in the upper Snake River Valley. The contract for construction was awarded December 13, 1971, and despite pending environmental lawsuits (which were eventually dismissed) work commenced in February of the following year.
All phases of the dam specifications were scheduled to be completed in May 1977 but by October 1975 the embankment was essentially finished. Workers then began the slow process of filling the reservoir.
Bureau of Reclamation memoranda book compiling the Teton Dam Reservoir level and capacity, the last entry being the day of the failure (NAID 2199668)
In the early morning of June 5, 1976, workers discovered two leaks in quick succession within the wall of rock that served as the dam abutment on the right side. Noted as no cause for concern, it wasn’t until a wet spot on the dam wall itself was discovered around 9:00 a.m. that serious alarms were raised. Quickly turning into a mud stream, by 10:30 a.m. it was flowing to the point that witnesses reported the leak sounding like a waterfall. Jerry Dursteller, an employee of the Gibbons and Reed Company which had been contracted to build the dam’s feeder pipeline and pump canal, arrived on scene at 10:00 a.m. and immediately began taking photographs. His collection of images, seen in whole within our collection, show the worsening of the leak.
Dursteller ran out of film at 11:50 a.m. and his last picture shows the gaping hole reaching the crest of the dam. On the reservoir side witnesses reported a small two foot diameter whirlpool had grown quickly to 20 feet in diameter, indicating an increasing volume of water leaking through the dam. A warning from project officials to local sheriff’s offices was soon elevated from ‘Prepare for Flooding’ to ‘Evacuate Everyone Downstream’ as there was nothing left to do, the dam was going to fail. At 11:57 over 250,000 acre feet of reservoir water, equivalent to 81.5 billion gallons, broke through the Teton Dam and rushed downstream.