Sun River near Simms, MT
River level and flood forecast · Cascade County
Normal2.9 ftas of Mon 12:30 PM
The river is 4.6 ft below flood stage (7.5 ft).
Flow: 332 cubic feet per second (USGS).
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 | 10.5 ft |
| Moderate flood stage | 8.5 ft |
| Flood stage | 7.5 ft |
| Action stage | 6 ft |
| Record crest (June 9, 1964) | 13.7 ft |
What floods at each level
From the National Weather Service, highest first.
- 12 ftMajor flooding. More than 100,000 acres flood.
- 10.8 ftAt 10.8 Feet - June 20 2018 - Flooding in the city of Sun River similar to 2011. Most streets under water. Photos estimate water 2 to 4 feet deep. Highway 200 Closed from the 89 Junction all the way to the 287 Junction. Roger's Pass had a culvert washout which closed that section.
- 10.7 ftJune 2018 - 1st and 2nd street flood in Sun River. Gravel washed away roadway, exposing optic cables. In Fort Shaw - North Fort Shaw Road completely destroyed. Culverts under roadway were exposed.
- 9.1 ftMay 27, 2019 - At 9.1 feet - Streets and homes in Sun River flooded. Not as bad as the 2018 flood. Highway 200 had water over the highway, with flaggers. Water around homes. Fields did flood.
- 9 ftMuch of the valley is flooded. Highway 200 flooded. Many homes as well as agricultural land floods.
- 8.5 ftHwy 200 through town of Sun River, between 1st St and 3rd St, under water. Significant inundation of town between river to W, N, and E of town to beyond W Carroll St/Steell St. Sun River-Cascade Rd inundated for approx 1/3 mile to south of town.
- 8 ftWater starting to cover Hwy 200 between 1st St and 2nd ST. River well out of banks W, N and E of town and filling old oxbows near town and Hwy 200.
- 7.5 ftRiver out of banks and across highway at Sun River (town). Water over Fairfield Road. River within banks at Simms and Fort Shaw. About two dozen homes in Sun River (town) become isolated.
- 7 ftMinor overflow between Fort Shaw and Sun River (town) where the river meanders and gets into the old river bed.
- 6.5 ftSome overflow between Fort Shaw and Sun Siver (town) where the river meanders and gets into the old river bed.
- 6 ftRiver is bankfull.
Highest crests on record
- 13.7 ft — June 9, 1964
- 12.48 ft — June 20, 1975
- 10.75 ft — June 20, 2018
- 9.87 ft — June 8, 2011
- 9.15 ft — May 27, 2019
Recent crests: 9.15 ft (May 27, 2019) · 10.75 ft (June 20, 2018) · 8.1 ft (May 12, 2018) · 5 ft (June 25, 2014) · 4.98 ft (June 9, 2013)
Up and down the river, and nearby
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (SSRM8); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.