Grizzly Bear Creek near Keystone, SD
River level and flood forecast · Pennington County
Normal2.2 ftas of Mon 2:40 PM
The river is 2.3 ft below flood stage (4.5 ft).
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 5 PM. Forecasts change as rain falls and as upstream water arrives.
Flood stages
| Major flood stage | 6 ft |
| Moderate flood stage | 5.5 ft |
| Flood stage | 4.5 ft |
| Action stage | 4 ft |
| Record crest (October 11, 2013) | 6.32 ft |
What floods at each level
From the National Weather Service, highest first.
- 6 ftMajor Flood Stage. Water will begin to flow down Main Street in Keystone.
- 5.5 ftModerate Flood Stage. Water will begin to cover bridges and parking areas in Keystone.
- 5 ftMinor flooding along the creek and downstream. Water begins to fill Grizzly Bear Creek in Keystone.
- 4.5 ftMinor flood stage. The creek will overflow and cut off access to Grizzly Gulch Road. Overflows the lower banks downstream from gage.
- 4 ftAction Stage and bankfull.
Highest crests on record
- 6.32 ft — October 11, 2013
- 5.78 ft — May 20, 2016
- 5.71 ft — May 28, 2019
- 5.68 ft — May 24, 2015
- 5.6 ft — July 11, 2001
Recent crests: 3.89 ft (April 7, 2024) · 3.33 ft (May 14, 2023) · 2.93 ft (June 7, 2022) · 3.53 ft (May 23, 2021) · 3.13 ft (July 5, 2020)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (GNKS2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.