Rivers in Iowa

Rock River at Rock Rapids

Lyon County, IowaNWS RAPI4USGS 06483290Sioux Falls office

Below flood stage
7.38ftStage

Observed Tue, Sep 22, 4:15 AM CDT

Flood stage
13.00 ft
Record crest
28.65 ft2024

Open the live map with the river flood outlook

Flood stages and impacts

CategoryStage
Major flood19.00 ft
Moderate flood16.00 ft
Minor flood13.00 ft
Action11.00 ft
  1. 28.00 ftWater reaches as far as Greene St on the west side of the river and the bridge on Hwy 9 in Rock Rapids is in danger of being overtopped.
  2. 27.00 ftSignificant flooding will be ongoing in Rock Rapids and water reaches as far Pearl St on the east side of the river and Tama St on the west side. Hwy 75 south of Rock Rapids may also become impassable.
  3. 26.00 ftWater reaches the bottom of the bridge on Hwy 9.
  4. 22.00 ftThe race track in Rock Rapids begins to flood as does N Boone St if water backs up Moon Creek
  5. 19.00 ftThe highest banks on the right side of the river will be overtopped with water beginning to encroach into the edges of Rock Rapids structures nearest the river.
  6. 16.00 ftThe higher banks on the left side become overtopped and more significant agriculture flooding begins.
  7. 15.00 ftMuch of the campground at Island Park in Rock Rapids is flooded.
  8. 13.00 ftThe lower banks become overtopped, including the lower lying areas of the Island Park Campground

Flood outlook

Chance of flooding, September to November

CategoryChance
Minor flooding8%
Moderate flooding5%
Major floodingUnder 5%

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 26, 2026.

Crest history

25 crests on NOAA’s list since 2002.

#DateStage
1June 22, 202428.65 ft
2June 17, 201426.98 ft
3September 25, 201022.25 ft
4September 14, 201921.54 ft
5June 22, 201820.80 ft
6March 15, 200719.79 ft
7March 14, 201919.78 ft
8April 8, 200617.81 ft
9June 6, 200816.49 ft
10March 22, 201115.66 ft
11May 28, 201214.92 ft
12March 2, 200414.27 ft
13June 24, 201313.86 ft
14July 7, 202013.80 ft
15April 13, 202313.40 ft
16September 17, 201613.02 ft
17February 10, 200912.83 ft
18July 25, 200512.57 ft
19July 6, 202212.11 ft
20August 20, 201511.96 ft
21May 22, 201711.46 ft
22July 1, 202510.61 ft
23March 30, 20029.95 ft
24April 20, 20039.66 ft
25September 4, 20219.26 ft

Most recent crests

  • July 1, 2025: 10.61 ft
  • June 22, 2024: 28.65 ft
  • April 13, 2023: 13.40 ft
  • July 6, 2022: 12.11 ft
  • September 4, 2021: 9.26 ft
  • July 7, 2020: 13.80 ft
  • September 14, 2019: 21.54 ft
  • March 14, 2019: 19.78 ft
  • June 22, 2018: 20.80 ft
  • May 22, 2017: 11.46 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.