Rivers in Iowa

Rock River at Rock Valley

Sioux County, IowaNWS RKVI4USGS 06483500Sioux Falls office

Below flood stage
6.40ftStage

Observed Sun, Sep 27, 11:00 AM CDT

Flood stage
16.00 ft
Record crest
27.70 ft2024

Open the live map with the river flood outlook

Flood stages and impacts

CategoryStage
Major flood19.00 ft
Moderate flood17.00 ft
Minor flood16.00 ft
Action14.00 ft
  1. 26.00 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.
  2. 23.00 ftElmwood Ave is flooded near the gauge and numerous houses on the north side of Rock Valley near the river are flooded.
  3. 21.00 ftWater begins to enter the northern portions of Rock Valley on the south side of the river.
  4. 20.00 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.
  5. 19.00 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.
  6. 18.00 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.
  7. 16.00 ftSignificant amounts of agricultural lands are flooded, and some rural roads are also threatened by high water.
  8. 13.00 ftThe lowest lying pasture and farm land will experience some minor flooding

Flood outlook

Chance of flooding, September to November

CategoryChance
Minor floodingUnder 5%
Moderate floodingUnder 5%
Major floodingUnder 5%

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued September 23, 2026.

Crest history

52 crests on NOAA’s list since 1936.

#DateStage
1June 22, 202427.70 ft
2June 17, 201422.72 ft
3June 22, 201821.20 ft
4March 15, 201920.61 ft
5September 26, 201020.24 ft
6May 9, 199319.97 ft
7September 25, 201019.89 ft
8March 23, 197918.91 ft
9June 20, 198318.85 ft
10June 14, 199418.27 ft
11June 18, 198418.06 ft
12March 15, 200717.96 ft
13April 24, 200117.74 ft
14April 7, 193617.32 ft
15January 1, 199717.00 ft
16March 30, 196216.91 ft
17March 19, 198616.88 ft
18April 9, 200616.44 ft
19April 24, 198516.07 ft
20June 8, 195315.99 ft
21June 21, 195415.86 ft
22March 21, 197815.32 ft
23March 29, 199715.17 ft
24February 24, 198214.61 ft
25June 6, 200814.54 ft

Most recent crests

  • July 2, 2025: 7.63 ft
  • June 22, 2024: 27.70 ft
  • June 1, 2022: 9.56 ft
  • April 10, 2021: 6.72 ft
  • July 8, 2020: 11.63 ft
  • March 15, 2019: 20.61 ft
  • June 22, 2018: 21.20 ft
  • May 2, 2016: 11.44 ft
  • August 21, 2015: 8.83 ft
  • June 17, 2014: 22.72 ft

Nearby

Upstream, downstream and the gauges around this one.

What this means

Forecasts by the Missouri Basin River Forecast Center. Forecasts are issued as needed during times of high water, but are not routinely available. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 48 hours into the future from the forecast issuance time. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 24 hours into the future from the forecast issuance time. Gauge reading may be affected by ice.

Sources

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.