Lexington, Ky. — During one of the most devastating floods in northern Rocky Mountain history, the Swift and Lower Two Medicine Dams both failed on June 8, 1964, killing at least 28 people. This record-breaking flooding resulted from extremely heavy rainfall and the melting of high levels of snow in the mountains. The failure of the Swift Dam, located west of Dupuyer, Mont., released approximately 30,000 acre-feet of water, while the Lower Two Medicine Dam near East Glacier Park had a capacity of 16,600 acre-feet of water.
“There are more than 87,000 dams in the United States today and people across the country rely on them for drinking water, hydroelectric power and other important benefits,” said Lori Spragens, executive director of the Association of State Dam Safety Officials (ASDSO). “The anniversary of these dam failures serves as an important reminder of the role that we all have to play in creating a future where all dams are safe.”
According to ASDSO’s data, there are 2,899 state-regulated dams in Montana, of which 105 are classified as high-hazard potential dams. The high-hazard potential classification indicates that a dam may cause loss of life if it were to fail.
Fortunately, good planning and improved dam safety programs at all levels of government have reduced the loss of life resulting from dam failures dramatically in recent years. To help protect lives and property in the event of a dam incident or failure, state dam safety program personnel and emergency management officials work with dam owners to develop and to maintain emergency action plans (EAPs). These important tools help save lives by putting evacuation and other safety procedures in place before an emergency occurs. As of 2013, 97 of the 105 high-hazard potential dams in Montana had an EAP.
According to a recent article in the Great Falls Tribune, Montana has also made physical repairs and improvements to its dams over the years to help keep the community safe. On June 17, during Montana Dam Safety Awareness Day at Ruby Dam, the state will commemorate the 1964 failures, and Gov. Steve Bullock will discuss the many improvements made to state dams since that time.