Lemhi River near Lemhi, ID
River level and flood forecast · Lemhi County
The river is 2.7 ft below flood stage (6.5 ft).
Forecast to hold near 3.8 ft through Mon, Oct 19, 6 PM.
Flow: 150 cubic feet per second (USGS).
The last 7 days and the forecast
NWS forecast issued Mon, Oct 12, 9:12 AM. Forecasts change as rain falls and as upstream water arrives.
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An email when the National Weather Service forecasts Lemhi River near Lemhi to flood, when it floods, and when it's over.
Flood stages
| Major flood stage | 10 ft |
| Moderate flood stage | 8.5 ft |
| Flood stage | 6.5 ft |
| Action stage | 6 ft |
| Record crest (June 21, 1984) | 7.19 ft |
What floods at each level
From the National Weather Service, highest first.
- 10 ftMainy bridges along Highway 28 will be overtopped and flooded from Lemhi to Tendoy.
- 8.5 ftPossible damage to irrigation diversion headgates and ditches.
- 7 ftExpect possible flooding to Highway 28 from Tendoy to Salmon.
- 6.5 ftExpect flooding to ranchland adjacent to the river from Tendoy to Salmon.
Highest crests on record
- 7.19 ft — June 21, 1984
- 7.07 ft — January 29, 2026
- 6.72 ft — July 6, 1975
- 6.7 ft — June 5, 2017
- 6.67 ft — June 24, 2011
Recent crests: 7.07 ft (January 29, 2026) · 4.76 ft (June 2, 2025) · 6.12 ft (June 13, 2022) · 5.81 ft (June 1, 2018) · 6.7 ft (June 5, 2017)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (LERI1); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.