Big Sky Dam

MIDDLE FK WEST FK GALLATIN RI· Madison, Montana· Built 1973· Earth· 52 ft tall
High Hazard Recreation Private

Key Takeaway

Big Sky Dam is classified as high hazard in Montana. It was completed in 1973 and is 53 years old. Its primary use is recreation. 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 52 ft (taller than 97% in MT)
Dam Length400 ft
Dam TypeEarth
Max Storage225 acre-ft
Normal Storage113 acre-ft
Surface Area10 acres
Drainage Area5 sq mi
Max Discharge1,331 cfs
Year Completed1973 (53 years old)
NID IDMT01395

Safety Information

High Hazard

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?

Emergency Action Plan: Yes
Last Inspection: August 28, 2020
State Regulated: Yes
Regulatory Agency: DNRC

Ownership

BIG SKY OF MONTANA INC

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Big Sky Dam?

Big Sky Dam 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 Big Sky Dam?

Big Sky Dam is owned by BIG SKY OF MONTANA INC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Big Sky Dam built?

Big Sky Dam was completed in 1973, making it 53 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 Big Sky Dam?

Big Sky Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Big Sky Dam?

Big Sky Dam has a dam height of 52 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 Big Sky Dam last inspected?

Big Sky Dam was last inspected on August 28, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.