Reservoir · Montana · United States · BOR RISE
Bighorn Lake Yellowtail Dam and Powerplant
82.4% full
Capacity
1,258.86 hm³
Volume stored
1037 hm³
Coordinates
45.307°N, 107.957°W
Last updated
2026-07-28
Current fill
82.4%vs 7 days ago
0.0%stable
vs 1 year ago
+1.2%year-over-year
7-day trend
→stable
Data source: BOR RISE — US Bureau of Reclamation — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-07-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 45.307, -107.957 · Open in Google Maps
About Bighorn Lake Yellowtail Dam and Powerplant
As of July 28, 2026, Bighorn Lake Yellowtail Dam and Powerplant is filled to 82.4% of its total capacity, holding roughly 1,037 hm³ of water out of a maximum 1,259 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it is 1.2 points above its level on the same date a year earlier.
Across the readings we hold for Bighorn Lake Yellowtail Dam and Powerplant — 1946 data points between July 31, 2021 and July 28, 2026 — the level has ranged from a low of 75.7% (May 8, 2024) to a high of 105.0% (June 24, 2023). On average the reservoir is fullest around July and at its lowest around April.
It is operated by BOR primarily for multiple purposes. It lies within the Montana basin at 45.307°N, 107.957°W.
Key facts
- Current fill level
- 82.4%
- Water stored
- 1,037 hm³
- Total capacity
- 1,259 hm³
- 7-day change
- No change
- Year-on-year
- ▲ 1.2 pts
- Primary use
- Multipurpose
- River basin
- Montana
- Operator
- BOR
- Coordinates
- 45.307°N, 107.957°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 82.4% | 1,037 |
| 27 Jul 2026 | 82.4% | 1,037 |
| 26 Jul 2026 | 82.3% | 1,036 |
| 25 Jul 2026 | 82.4% | 1,037 |
| 24 Jul 2026 | 82.4% | 1,037 |
| 23 Jul 2026 | 82.4% | 1,038 |
| 22 Jul 2026 | 82.4% | 1,038 |
| 21 Jul 2026 | 82.4% | 1,038 |
| 20 Jul 2026 | 82.5% | 1,038 |
| 19 Jul 2026 | 82.5% | 1,038 |
| 18 Jul 2026 | 82.5% | 1,038 |
| 17 Jul 2026 | 82.4% | 1,038 |
Frequently asked questions
What is the current water level of Bighorn Lake Yellowtail Dam and Powerplant?
As of July 28, 2026, Bighorn Lake Yellowtail Dam and Powerplant is at 82.4% of its capacity, holding approximately 1,037 hm³ of water, according to BOR RISE (US Bureau of Reclamation) data.
Is Bighorn Lake Yellowtail Dam and Powerplant reservoir full?
No. As of July 28, 2026, Bighorn Lake Yellowtail Dam and Powerplant is high at 82.4% of its capacity, so it is not full.
Is the water level at Bighorn Lake Yellowtail Dam and Powerplant rising or falling?
The level at Bighorn Lake Yellowtail Dam and Powerplant has been broadly stable over the latest week on record (0.0 points).
How much water can Bighorn Lake Yellowtail Dam and Powerplant hold?
Bighorn Lake Yellowtail Dam and Powerplant has a total capacity of 1,259 hm³.
Where is Bighorn Lake Yellowtail Dam and Powerplant reservoir located?
Bighorn Lake Yellowtail Dam and Powerplant is located in Montana, United States, within the Montana basin (coordinates 45.307°N, 107.957°W).
What is Bighorn Lake Yellowtail Dam and Powerplant used for?
Bighorn Lake Yellowtail Dam and Powerplant is used primarily for multiple purposes, and is managed by BOR.