From the Lawton Constitution
By James Finck, Ph.D. Aug 4, 2026
Every year I try to make a pilgrimage to eastern Idaho to visit my parents and escape the Oklahoma heat.
Idaho Falls sits at almost 5,000 feet, and my grandpa used to have a cabin up in the mountains that remains one of my favorite places on earth. Unfortunately, I arrived during a heat wave, but it still cools down in the evenings, and the dry heat is far more tolerable than what’s going on in Oklahoma.
This year I found several towns in the area holding memorials for the 50th anniversary of the collapse of the Teton Dam, one of the worst man-made disasters in U.S. history. My mother grew up in this area, so I had heard stories about the collapse before, but I had never paid much attention to them. Considering the anniversary, however, I felt it was worth learning more.
Being a farming community, local leaders determined that damming the Teton River could help control the spring runoff from melting mountain snow while also providing irrigation throughout the year. The 305-foot-high earth-fill embankment dam was completed in November 1975, and the reservoir began filling soon afterward.
As I am a historian rather than an engineer, my best understanding is that the dam was built on volcanic rock. Because volcanic rock is permeable and allows water to seep through, engineers attempted to grout the underlying rock to reduce leakage. However, heavier-than-expected snow runoff caused the reservoir to fill quicker than anticipated, and water found its way through the foundation. On June 3 and 4, 1976, springs appeared downstream, but because the water was clear, officials believed the seepage was within acceptable limits. The following day, June 5, however, a muddy leak appeared, signaling that soil was being washed out from within the dam. Crews rushed to stop the leak while residents downstream were ordered to evacuate. Despite frantic efforts by operators using bulldozers to plug the widening breach, the dam completely failed just before noon, sending a wall of water into the valley below.
When the dam collapsed, it released roughly 80 billion gallons of water down the Teton River Canyon. The flooding claimed 11 lives, caused approximately $2 billion in property damage, and fundamentally altered the geography of the region. The downstream impact was immediate and devastating. The small community of Wilford, located closest to the riverbank, was essentially leveled, becoming the site of five of the disaster’s
fatalities. Farther downstream, a 15-foot wave struck Sugar City, virtually erasing the town and destroying nearly every home and farm. In Rexburg, five feet of muddy water submerged nearly 80% of the city’s structures. The devastation was compounded when floodwater swept thousands of heavy logs from a local lumberyard through the streets like battering rams. The logs ruptured fuel storage tanks, igniting floating oil fires that burned buildings even as they stood surrounded by floodwater.
Even farther downstream, the Teton River empties into the Snake River, sending an enormous surge of water through Idaho Falls and temporarily submerging the city’s waterfalls. The high water forced the hydroelectric power plant at the falls to shut down, interrupting power generation until the river returned to safer levels. Thousands of residents were forced to evacuate as homes, businesses, farmland, and infrastructure were damaged by the flooding. Although Idaho Falls experienced significant flooding, the advance warning gave residents time to prepare, allowing the city to avoid the catastrophic destruction and loss of life suffered by communities closer to the dam.
While the flooding was devastating, the recovery efforts highlighted the remarkable strength of the local community, resulting in a legacy of service that continues to define the region today. Something similar to the Oklahoma Standard we have seen several times after major tornadoes.
Amid the destruction, an extraordinary humanitarian response took shape. Because the region was predominantly populated by members of The Church of Jesus Christ of Latter-day Saints, residents relied on their existing church networks to bypass bureaucratic delays. Local church leaders quickly accounted for every family in their boundaries, while an estimated 10,000 outside volunteers poured into the disaster zone each weekend. Armed with shovels and heavy equipment, these volunteer crews systematically cleaned mud-filled homes one by one. Meanwhile, Ricks College, now BYU–Idaho, located safely on a hill above Rexburg, was transformed into a massive refugee camp. The campus housed more than 10,000 displaced residents, and its cafeteria produced as many as 30,000 hot meals each day for victims and relief workers.
Ultimately, the Teton Dam disaster rewrote the rules of both engineering and disaster response. The dam was never rebuilt, leaving the scarred canyon as a permanent reminder of the disaster, and the failure prompted sweeping reforms in federal dam safety inspections and engineering practices. Just as importantly, the rapid, self-reliant cleanup astonished federal officials and became a model for future large-scale humanitarian relief efforts.
James Finck is a professor of American history at the University of Science and Arts of Oklahoma. He can be reached at james.finck@swoknews.com
Historically Speaking 