Rock River at Rock Valley, IA
River level and flood forecast · Sioux County
Normal5.3 ftas of Mon 3 PM
The river is 10.7 ft below flood stage (16 ft).
Flow: 557 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 | 19 ft |
| Moderate flood stage | 17 ft |
| Flood stage | 16 ft |
| Action stage | 14 ft |
| Record crest (June 22, 2024) | 27.7 ft |
What floods at each level
From the National Weather Service, highest first.
- 26 ftSignificant flooding will be ongoing in Rock Valley with most houses and businesses north of downtown flooded. Portions of the bridge on 340th St are overtopped.
- 23 ftElmwood Ave is flooded near the gauge and numerous houses on the north side of Rock Valley near the river are flooded.
- 21 ftWater begins to enter the northern portions of Rock Valley on the south side of the river.
- 20 ftHwy 18 west of Rock Valley is flooded. The lower portions of 300th Ave in Rock Valley north of the river and west of Elmwood Ave may flood. Major agricultural flooding is ongoing throughout the floodplain.
- 19 ftRock Valley begins to experience increasing flood problems and at least a couple of houses nearest the river begin to flood. Sandbagging of storm sewers in the city begins. Portions of 360th will be flooded.
- 18 ftWater reaches the backyards of some houses north of the river and west of Elmwood Ave in Rock Valley and some outbuildings are flooded. The Rivers Bend Campground on the northwest side of Rock Valley begins to flood.
- 16 ftSignificant amounts of agricultural lands are flooded, and some rural roads are also threatened by high water.
- 13 ftThe lowest lying pasture and farm land will experience some minor flooding
Highest crests on record
- 27.7 ft — June 22, 2024
- 22.72 ft — June 17, 2014
- 21.2 ft — June 22, 2018
- 20.61 ft — March 15, 2019
- 20.24 ft — September 26, 2010
Recent crests: 7.63 ft (July 2, 2025) · 27.7 ft (June 22, 2024) · 9.56 ft (June 1, 2022) · 6.72 ft (April 10, 2021) · 11.63 ft (July 8, 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 (RKVI4); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.