RIVER GAUGE · BIG LOST RIVER
Big Lost River below Mackay Reservoir
Custer County, Idaho
Water level2.27 ft
Flow280 cfs
Last readingSep 16, 2026, 4:45 PM UTC (last recorded)
Action3.8 ft1,199 cfs
Minor flood4.3 ft1,574 cfs
The past week
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What floods at each level
- 4.3 ft
Lowland flooding below Mackay Dam through the Darlington Flats. US Highway 93 may be impacted at the curve by Leslie between 3900 North and 4050 North.
- 3.8 ft
Near bankfull from Mackay Dam through the Darlington Flats. Water is likely to start to seep in low-lying areas in the Darlington Flats.
Highest crests on record
| Date | Level | Flow |
|---|---|---|
| Jun 5, 1986 | 6.08 ft | 2,990 cfs |
| Jun 16, 1974 | 5.93 ft | 2,790 cfs |
| Jun 13, 1965 | 5.89 ft | 2,640 cfs |
More on Big Lost River
DownstreamBig Lost River near Arco
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