Whetstone River above Big Stone City, SD
River level and flood forecast · Grant County
Normal1.2 ftas of Mon 3 PM
The river is 10.8 ft below flood stage (12 ft).
Flow: 5 cubic feet per second (USGS).
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 6 PM. Forecasts change as rain falls and as upstream water arrives.
Flood stages
| Major flood stage | 20 ft |
| Moderate flood stage | 15 ft |
| Flood stage | 12 ft |
| Action stage | 11 ft |
| Record crest (June 1, 1919) | 26 ft |
What floods at each level
From the National Weather Service, highest first.
- 12 ftThe road 2 miles west and 1 mile south of the gauge floods.
Highest crests on record
- 26 ft — June 1, 1919
- 15.93 ft — April 8, 2001
- 15.08 ft — March 13, 2007
- 14.32 ft — April 8, 1969
- 14.21 ft — April 6, 1997
Recent crests: 9.41 ft (June 26, 2025) · 8.57 ft (March 8, 2020) · 11.97 ft (March 22, 2019) · 7.63 ft (April 23, 2018) · 11.25 ft (September 25, 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 (BGCS2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.