Major Flood
22 ft
Current Water Level
Gage Height
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Streamflow
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Last Reading
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FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
16 ft
Minor Flood
12 ft
Action Stage
10 ft
What Floods at Each Level
26 ft
Hwy 10 is flooded and substantial flooding is ongoing near the river throughout Alton.
24 ft
Several houses on the north side of Alton flood. Water approaches Hwy 10 on the north side of Alton. The railroad tracks are also flooded.
22 ft
More substantial street flooding begins in Alton including 3rd Ave south of the bridge. Additional structures are also in danger of flooding.
20 ft
The lower levees in Alton may begin to be overtopped flooding some nearby industrial businesses. Hwy 60 south of Alton is flooded. Portions of Division St in Alton may also begin to flood and the bridge on 3rd Ave may also be closed.
18 ft
The entire flood plain is under water and the river is about 1/2 mile wide. The flooding still primarily only affects agricultural land and county roads.
16 ft
Significant amounts of crop and pasture land are flooded.
15 ft
410th Street and Larch Avenue is inundated. Also 440th Street and Kingbird Avenue is flooded, and the water reaches the bottom of the bridge at CR L14 and 440th Street.
12 ft
Flooding begins to affect the lower lying agricultural lands along the river.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Jun 21, 2024 | 26.81 ft | — |
| Sep 19, 2018 | 21.96 ft | 21,700 cfs |
| Mar 13, 2019 | 20.87 ft | 24,900 cfs |
About This Gauge
Get Flood Alerts for Floyd River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Floyd River at Alton?
The Floyd River at Alton gauge is maintained by USGS (site 06600100) and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Floyd River at Alton?
The NWS-defined flood stage for Floyd River at Alton is 12 feet. Action stage begins at 10 feet. Moderate flooding starts at 16 feet, and major flooding at 22 feet.
How do I get alerts when Floyd River rises?
Download StormCast free on Google Play, go to River Gauges, and add Floyd River at Alton to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category.
Where is the Floyd River at Alton gauge located?
The gauge is located in Sioux County, Iowa at coordinates 42.9819°N, 96.0008°W. USGS site number: 06600100. Data is provided by the U.S. Geological Survey and the National Weather Service.
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Source & Notes
Data provided by: Observations courtesy of U.S. Geological Survey, Observations courtesy of U.S. Army Corps of Engineers
- 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.