Yellowtail
Key Takeaway
Yellowtail is classified as high hazard in Montana. It was completed in 1966 and is 60 years old. Its primary use is hydroelectric. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 491 ft (taller than 99.9% in MT) |
| Dam Length | 1,480 ft |
| Dam Type | Concrete |
| Max Storage | 1.3M acre-ft |
| Normal Storage | 1.0M acre-ft |
| Surface Area | 17,958 acres |
| Drainage Area | 19,650 sq mi |
| Max Discharge | 93,000 cfs |
| Year Completed | 1966 (60 years old) |
| NID ID | MT00576 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
RECLAMATION
Federal Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Yellowtail?
Yellowtail is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Yellowtail?
Yellowtail is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Yellowtail built?
Yellowtail was completed in 1966, making it 60 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of Yellowtail?
Yellowtail serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Yellowtail?
Yellowtail has a dam height of 491 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Yellowtail last inspected?
Yellowtail was last inspected on August 25, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.