Reservoir · Utah · United States · BOR RISE
Lost Lake
63.4% full
Capacity
1.42 hm³
Volume stored
1 hm³
Coordinates
40.674°N, 110.941°W
Last updated
2026-09-11
Current fill
63.4%vs 7 days ago
-4.9%losing
vs 1 year ago
+12.7%year-over-year
7-day trend
↓falling
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: 2026-09-11.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 40.674, -110.941 · Open in Google Maps
About Lost Lake
As of September 11, 2026, Lost Lake is filled to 63.4% of its total capacity, holding roughly 1 hm³ of water out of a maximum 1 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has fallen by 4.9 percentage points, and it is 12.7 points above its level on the same date a year earlier.
Across the readings we hold for Lost Lake — 1823 data points between September 15, 2021 and September 11, 2026 — the level has ranged from a low of 46.5% (April 30, 2023) to a high of 102.8% (June 5, 2024). On average the reservoir is fullest around June and at its lowest around October.
It is operated by BOR primarily for multiple purposes. It lies within the Utah basin at 40.674°N, 110.941°W.
Key facts
- Current fill level
- 63.4%
- Water stored
- 1 hm³
- Total capacity
- 1 hm³
- 7-day change
- ▼ 4.9 pts
- Year-on-year
- ▲ 12.7 pts
- Primary use
- Multipurpose
- River basin
- Utah
- Operator
- BOR
- Coordinates
- 40.674°N, 110.941°W
- Last updated
- September 11, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 11 Sep 2026 | 63.4% | 1 |
| 10 Sep 2026 | 64.1% | 1 |
| 9 Sep 2026 | 64.8% | 1 |
| 8 Sep 2026 | 65.5% | 1 |
| 7 Sep 2026 | 66.2% | 1 |
| 6 Sep 2026 | 66.9% | 1 |
| 5 Sep 2026 | 67.6% | 1 |
| 4 Sep 2026 | 68.3% | 1 |
| 3 Sep 2026 | 69.7% | 1 |
| 2 Sep 2026 | 71.1% | 1 |
| 1 Sep 2026 | 71.8% | 1 |
| 31 Aug 2026 | 73.2% | 1 |