Little Sioux River at Spencer

1. 22.00 ftIncreasingly severe flooding begins on the north side of the river in Spencer with water beginning to pour down Grand Ave, roughly to the intersection of 1st St.
2. 21.00 ftCatastrophic flooding is ongoing in Spencer with most of the south side of the city flooded and the highest levees overtopped. Water nears the feedhorn of the automated sensor and thus river level data may be lost.
3. 19.50 ftSignificant flooding is ongoing in Spencer with water all the way to 8th St and S Grand Ave south of the river. Flooding also begins to spill into the lowest portions on the north side of the river such as Park St and also up 3rd Ave W.
4. 18.00 ftThe berms on the south side of the river in Spencer are overtopped and several structures on the north side of the river are also flooded. The Spencer Golf and Country Club begins flooding.
5. 17.50 ftHwy 18 east of Spencer near Hawk Valley WMA begins to flood.
6. 17.00 ftWater approaches the top of the lowest berms on the south side of the river in Spencer. West 4th St on the southwest side of Spencer floods.
7. 16.00 ftWater begins to approach Hwy 18 near Hawk Valley WMA east of Spencer.
8. 14.50 ftCounty Road B40 southeast of Spencer begins flooding. The playground at East Leach Park and the lowest portions of 4th St would flood if levee protection fails.
9. 14.00 ftCity sewers in Spencer can begin to back up. Highway 18 between Spencer and Dickens can start flooding if flows on the tributary creeks are also very high.
10. 12.00 ftMost of the floodplain through the center of Spencer is flooded.
11. 10.00 ftThe floodplain and some of the walking trails within Spencer city park are flooded. Some rural agricultural areas also begin to flood.
12. 9.00 ftThe lower left bank overflows and very minor flooding of low lands begins.

Chance of flooding, September to November

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

Most recent crests

• July 31, 2025: 9.13 ft
• June 22, 2024: 22.20 ft
• May 16, 2023: 10.89 ft
• March 10, 2020: 11.70 ft
• March 15, 2019: 17.45 ft
• June 26, 2018: 17.40 ft
• May 23, 2017: 12.20 ft
• February 22, 2016: 11.47 ft
• June 20, 2014: 15.18 ft
• June 28, 2013: 12.10 ft

• UpstreamLittle Sioux River at Spencer / Highway 18
• DownstreamLittle Sioux River at Linn Grove
• Ocheyedan River at Spencer
• Little Sioux River at Spencer
• Willow Creek (North Central IA) at Cornell
• Ocheyedan River at Everly
• Little Sioux River at Milford
• Milford Creek at Lower Gar Lake Outlet
• East Okoboji Lake at East/West Okoboji Lake Channel

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.

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service.