Floyd River at Alton, IA

Sioux County, Iowa · USGS gauge 06600100 · NWS ALTI4 · Floyd River flood status · Iowa river levels

Is Floyd River at Alton, IA flooding right now?

Floyd River at Alton, IA measured 6.37 ft on 2026-09-11 01:00:00 UTC. That observation was 5.6 ft below its 12 ft flood stage. This is the latest available reading, not a guarantee of current conditions.

Gauge height

6.37 ft

as of 70 min ago

Streamflow

232 cfs

data refreshed 8 min ago

Minor flooding here begins at 12 ft, with major flooding at 22 ft. The highest crest on record was 26.81 ft on Sat, Jun 22, 2024.

Streamflow outlook

NOAA National Water Model forecast, issued 14 hours ago. The NWM models discharge for every river reach in the country, including the many gauges the National Weather Service does not forecast individually. It is a model, not an official NWS river forecast, and it predicts flow rather than water level.

Flood stages at this gauge

Category	Stage	Current distance
Action	10 ft	3.6 ft below
Minor flood	12 ft	5.6 ft below
Moderate flood	16 ft	9.6 ft below
Major flood	22 ft	15.6 ft below

New to these numbers? What does flood stage mean? · How to read a river gauge · Why is the river rising?

Highest crests on record

Stage	Date
26.81 ft	2024-06-22
21.96 ft	2018-09-20
20.87 ft	2019-03-14
20.5 ft	2018-06-21
19.19 ft	2013-05-27

Nearby gauges

Gauge	Distance	County
West Branch Floyd River near Struble, IA	9.8 mi	Sioux County
Little Floyd River near Sanborn, IA	19.7 mi	O'Brien County
Burr Oak Creek near Perkins, IA	20.2 mi	Sioux County
Rock River near Rock Valley, IA	21.9 mi	Sioux County
Big Sioux River near Hawarden, IA	25.1 mi	Union County

Provisional data: Real-time readings are provisional and subject to revision by the USGS — sensors can be affected by ice, debris, or equipment malfunction. Do not rely on this site for decisions involving personal safety; follow official guidance from the National Weather Service and local authorities.

Sources: USGS monitoring location · NWS gauge & forecast