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Rock River at Afton

Highest listed crest 13.51 ftFlood stage 9.0 ft121 crests since 1914

The Rock River at Afton crested at major flood stage 3 times among the 121 crests the National Weather Service lists from 1914 to 2026. The highest, 13.51 ft on June 21, 2008, was major flooding, 4.51 feet above flood stage. 10 other gauges on the Rock River crested above flood stage within a week of it, 4 at their own highest listed crest.

The gauge

Highest listed crest
13.51 ft
June 21, 2008; 16,700 cubic feet per second
Flood stage
9.0 ft
Major flooding from 12.2 ft
Crests at major
3
30th of 143 gauges in Wisconsin
Most recent flood crest
April 18, 2026
12.11 ft, moderate flooding
Location
Rock County
Near Janesville (5.7 mi), Beloit (6.8 mi), Roscoe (13.4 mi)

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Rock River at Afton
Action stage8.019Apr 7, 2017The level at which the NWS or its partners begin to take action
Flood stage (minor)9.043Jul 16, 2024Minimal or no property damage, but possibly some public threat
Moderate flood stage11.112Apr 18, 2026Some inundation of structures and roads near the stream
Major flood stage12.23Jun 21, 2008Extensive inundation of structures and roads

Every listed crest

121 crests from 1914 to 2026. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Rock River at Afton, 1914 to 2026 2468101214ft Flood stage 9.0 ftMajor 12.2 ft Sep 15, 1914: 7.60 ft, below flood stage; 7,050 cubic feet per secondSep 13, 1915: 11.00 ft, minor flooding; 10,500 cubic feet per secondFeb 5, 1916: 13.05 ft, major floodingApr 1, 1916: 10.12 ft, minor flooding; 9,270 cubic feet per secondApr 1, 1917: 10.00 ft, minor flooding; 9,050 cubic feet per secondMar 25, 1918: 11.50 ft, moderate flooding; 12,700 cubic feet per secondApr 15, 1919: 5.90 ft, below flood stage; 3,560 cubic feet per secondApr 1, 1920: 10.30 ft, minor flooding; 10,100 cubic feet per secondMay 2, 1921: 9.30 ft, minor flooding; 8,200 cubic feet per secondApr 11, 1922: 9.70 ft, minor flooding; 8,640 cubic feet per secondApr 12, 1923: 10.60 ft, minor flooding; 10,400 cubic feet per secondAug 20, 1924: 8.70 ft, action stage; 7,100 cubic feet per secondFeb 23, 1925: 7.00 ft, below flood stage; 4,720 cubic feet per secondMar 23, 1926: 7.40 ft, below flood stage; 5,180 cubic feet per secondMar 20, 1927: 7.80 ft, below flood stage; 5,750 cubic feet per secondApr 14, 1928: 8.40 ft, action stage; 6,670 cubic feet per secondMar 23, 1929: 11.80 ft, moderate flooding; 13,000 cubic feet per secondMar 4, 1930: 7.00 ft, below flood stage; 4,620 cubic feet per secondMar 28, 1931: 3.50 ft, below flood stage; 1,380 cubic feet per secondMar 27, 1932: 6.80 ft, below flood stage; 4,380 cubic feet per secondMay 20, 1933: 10.00 ft, minor flooding; 8,990 cubic feet per secondApr 11, 1934: 5.36 ft, below flood stage; 2,890 cubic feet per secondMar 10, 1935: 8.52 ft, action stage; 6,350 cubic feet per secondMar 26, 1936: 7.07 ft, below flood stage; 4,600 cubic feet per secondMar 4, 1937: 10.23 ft, minor flooding; 8,510 cubic feet per secondJan 24, 1938: 10.44 ft, minor flooding; 9,190 cubic feet per secondFeb 25, 1939: 8.00 ft, action stage; 5,800 cubic feet per secondAug 26, 1940: 10.80 ft, minor flooding; 10,700 cubic feet per secondApr 4, 1941: 7.43 ft, below flood stage; 4,990 cubic feet per secondMar 25, 1942: 5.94 ft, below flood stage; 3,300 cubic feet per secondMar 16, 1943: 11.04 ft, minor flooding; 11,100 cubic feet per secondMar 14, 1944: 9.19 ft, minor flooding; 7,620 cubic feet per secondMar 21, 1945: 6.31 ft, below flood stage; 3,830 cubic feet per secondMar 23, 1946: 10.46 ft, minor flooding; 10,000 cubic feet per secondMar 19, 1948: 10.20 ft, minor flooding; 9,390 cubic feet per secondMar 5, 1949: 7.79 ft, below flood stage; 5,520 cubic feet per secondOct 16, 1949: 6.98 ft, below flood stage; 4,490 cubic feet per secondJul 27, 1950: 8.24 ft, action stage; 6,350 cubic feet per secondMay 4, 1951: 9.16 ft, minor flooding; 7,850 cubic feet per secondMar 29, 1952: 10.39 ft, minor flooding; 9,810 cubic feet per secondFeb 20, 1953: 8.06 ft, action stage; 6,200 cubic feet per secondJul 14, 1954: 6.93 ft, below flood stage; 4,620 cubic feet per secondOct 11, 1954: 6.82 ft, below flood stage; 4,480 cubic feet per secondMay 16, 1956: 6.80 ft, below flood stage; 4,460 cubic feet per secondJun 14, 1957: 5.96 ft, below flood stage; 3,460 cubic feet per secondMar 6, 1958: 4.76 ft, below flood stage; 2,230 cubic feet per secondApr 10, 1959: 11.77 ft, moderate flooding; 12,100 cubic feet per secondApr 6, 1960: 10.00 ft, minor flooding; 8,990 cubic feet per secondMar 29, 1961: 8.09 ft, action stage; 6,050 cubic feet per secondApr 5, 1962: 10.13 ft, minor flooding; 9,060 cubic feet per secondApr 1, 1963: 6.56 ft, below flood stage; 4,070 cubic feet per secondMar 14, 1964: 5.09 ft, below flood stage; 2,530 cubic feet per secondSep 26, 1965: 8.11 ft, action stage; 5,990 cubic feet per secondMar 28, 1966: 7.46 ft, below flood stage; 5,200 cubic feet per secondJun 17, 1967: 7.39 ft, below flood stage; 5,060 cubic feet per secondJul 3, 1968: 7.67 ft, below flood stage; 5,050 cubic feet per secondApr 18, 1969: 7.43 ft, below flood stage; 4,740 cubic feet per secondMay 20, 1970: 5.85 ft, below flood stage; 3,010 cubic feet per secondMar 29, 1971: 8.33 ft, action stage; 5,910 cubic feet per secondSep 30, 1972: 7.76 ft, below flood stage; 5,170 cubic feet per secondMay 8, 1973: 10.81 ft, minor flooding; 9,680 cubic feet per secondMar 12, 1974: 9.88 ft, minor flooding; 8,180 cubic feet per secondApr 1, 1975: 11.25 ft, moderate flooding; 10,400 cubic feet per secondMar 5, 1976: 8.93 ft, action stage; 6,760 cubic feet per secondApr 8, 1977: 5.35 ft, below flood stage; 2,600 cubic feet per secondJul 2, 1978: 8.69 ft, action stage; 6,420 cubic feet per secondApr 5, 1979: 11.86 ft, moderate flooding; 11,500 cubic feet per secondSep 30, 1980: 8.26 ft, action stage; 5,820 cubic feet per secondApr 11, 1982: 9.79 ft, minor flooding; 5,040 cubic feet per secondApr 13, 1983: 8.56 ft, action stage; 6,230 cubic feet per secondFeb 27, 1984: 7.89 ft, below flood stage; 5,340 cubic feet per secondMar 14, 1985: 9.58 ft, minor flooding; 7,730 cubic feet per secondMar 27, 1986: 10.58 ft, minor flooding; 9,290 cubic feet per secondOct 9, 1986: 10.74 ft, minor flooding; 9,560 cubic feet per secondApr 6, 1988: 7.00 ft, below flood stage; 4,210 cubic feet per secondApr 2, 1989: 6.86 ft, below flood stage; 4,060 cubic feet per secondMar 22, 1990: 8.38 ft, action stage; 5,980 cubic feet per secondApr 19, 1991: 7.92 ft, below flood stage; 5,380 cubic feet per secondNov 12, 1991: 7.23 ft, below flood stage; 4,490 cubic feet per secondApr 23, 1993: 11.41 ft, moderate flooding; 10,700 cubic feet per secondMar 21, 1994: 8.27 ft, action stage; 5,830 cubic feet per secondMay 16, 1995: 6.60 ft, below flood stage; 3,770 cubic feet per secondJun 24, 1996: 10.09 ft, minor flooding; 8,500 cubic feet per secondFeb 21, 1997: 8.63 ft, action stage; 6,330 cubic feet per secondApr 21, 1998: 9.24 ft, minor flooding; 7,220 cubic feet per secondApr 28, 1999: 9.17 ft, minor flooding; 7,120 cubic feet per secondJun 2, 2000: 10.73 ft, minor flooding; 9,540 cubic feet per secondApr 17, 2001: 7.97 ft, below flood stage; 5,440 cubic feet per secondMar 18, 2002: 7.19 ft, below flood stage; 4,440 cubic feet per secondMay 14, 2003: 6.52 ft, below flood stage; 3,680 cubic feet per secondJun 1, 2004: 10.96 ft, minor flooding; 8,830 cubic feet per secondFeb 14, 2005: 7.67 ft, below flood stage; 5,050 cubic feet per secondApr 16, 2006: 7.33 ft, below flood stage; 4,610 cubic feet per secondAug 30, 2007: 10.01 ft, minor flooding; 8,380 cubic feet per secondJan 23, 2008: 12.21 ft, major flooding; 12,600 cubic feet per secondJun 21, 2008: 13.51 ft, major flooding; 16,700 cubic feet per secondMar 25, 2009: 11.15 ft, moderate flooding; 10,300 cubic feet per secondJul 31, 2010: 10.54 ft, minor flooding; 9,560 cubic feet per secondMar 29, 2011: 9.39 ft, minor flooding; 7,990 cubic feet per secondMay 12, 2012: 7.03 ft, below flood stage; 4,710 cubic feet per secondApr 18, 2013: 11.84 ft, moderate flooding; 12,000 cubic feet per secondJul 8, 2014: 8.95 ft, action stage; 7,000 cubic feet per secondApr 18, 2015: 7.32 ft, below flood stage; 4,720 cubic feet per secondOct 18, 2015: 11.84 ft, moderate floodingApr 13, 2016: 8.43 ft, action stage; 6,200 cubic feet per secondApr 7, 2017: 8.94 ft, action stageJul 21, 2017: 9.36 ft, minor flooding; 7,480 cubic feet per secondFeb 21, 2018: 11.12 ft, moderate flooding; 10,500 cubic feet per secondMar 1, 2018: 9.29 ft, minor flooding; 7,460 cubic feet per secondMay 21, 2018: 9.79 ft, minor flooding; 8,177 cubic feet per secondSep 12, 2018: 11.20 ft, moderate flooding; 10,700 cubic feet per secondJan 26, 2019: 9.86 ft, minor flooding; 3,290 cubic feet per secondMar 25, 2019: 11.07 ft, minor flooding; 10,500 cubic feet per secondOct 15, 2019: 10.48 ft, minor flooding; 9,400 cubic feet per secondMar 29, 2020: 9.36 ft, minor flooding; 7,560 cubic feet per secondMar 18, 2021: 7.43 ft, below flood stage; 4,860 cubic feet per secondApr 13, 2022: 7.27 ft, below flood stage; 4,810 cubic feet per secondApr 10, 2024: 9.12 ft, minor flooding; 7,210 cubic feet per secondJun 13, 2024: 9.50 ft, minor flooding; 7,780 cubic feet per secondJul 16, 2024: 10.79 ft, minor flooding; 9,940 cubic feet per secondApr 18, 2026: 12.11 ft, moderate flooding; 12,517 cubic feet per second Highest, 13.51 ft, Jun 21, 2008 192019401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Rock River at Afton 1910s: 5 1920s: 5 1930s: 3 1940s: 5 1950s: 3 1960s: 2 1970s: 4 1980s: 4 1990s: 4 2000s: 6 2010s: 12 12 2020s: 5 1910s1920s1930s1940s1950s1960s1970s1980s1990s2000s2010s2020s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

The 50 highest of 121 listed crests.

Highest listed crests, Rock River at Afton
1Jun 21, 200813.51+4.51Major16,700
2Feb 5, 191613.05+4.05Major—
3Jan 23, 200812.21+3.21Major12,600
4Apr 18, 202612.11+3.11Moderate12,517
5Apr 5, 197911.86+2.86Moderate11,500
6Apr 18, 201311.84+2.84Moderate12,000
7Oct 18, 201511.84+2.84Moderate—
8Mar 23, 192911.80+2.80Moderate13,000
9Apr 10, 195911.77+2.77Moderate12,100
10Mar 25, 191811.50+2.50Moderate12,700
11Apr 23, 199311.41+2.41Moderate10,700
12Apr 1, 197511.25+2.25Moderate10,400
13Sep 12, 201811.20+2.20Moderate10,700
14Mar 25, 200911.15+2.15Moderate10,300
15Feb 21, 201811.12+2.12Moderate10,500
16Mar 25, 201911.07+2.07Minor10,500
17Mar 16, 194311.04+2.04Minor11,100
18Sep 13, 191511.00+2.00Minor10,500
19Jun 1, 200410.96+1.96Minor8,830
20May 8, 197310.81+1.81Minor9,680
21Aug 26, 194010.80+1.80Minor10,700
22Jul 16, 202410.79+1.79Minor9,940
23Oct 9, 198610.74+1.74Minor9,560
24Jun 2, 200010.73+1.73Minor9,540
25Apr 12, 192310.60+1.60Minor10,400
26Mar 27, 198610.58+1.58Minor9,290
27Jul 31, 201010.54+1.54Minor9,560
28Oct 15, 201910.48+1.48Minor9,400
29Mar 23, 194610.46+1.46Minor10,000
30Jan 24, 193810.44+1.44Minor9,190
31Mar 29, 195210.39+1.39Minor9,810
32Apr 1, 192010.30+1.30Minor10,100
33Mar 4, 193710.23+1.23Minor8,510
34Mar 19, 194810.20+1.20Minor9,390
35Apr 5, 196210.13+1.13Minor9,060
36Apr 1, 191610.12+1.12Minor9,270
37Jun 24, 199610.09+1.09Minor8,500
38Aug 30, 200710.01+1.01Minor8,380
39Apr 1, 191710.00+1.00Minor9,050
40May 20, 193310.00+1.00Minor8,990
41Apr 6, 196010.00+1.00Minor8,990
42Mar 12, 19749.88+0.88Minor8,180
43Jan 26, 20199.86+0.86Minor3,290
44Apr 11, 19829.79+0.79Minor5,040
45May 21, 20189.79+0.79Minor8,177
46Apr 11, 19229.70+0.70Minor8,640
47Mar 14, 19859.58+0.58Minor7,730
48Jun 13, 20249.50+0.50Minor7,780
49Mar 29, 20119.39+0.39Minor7,990
50Jul 21, 20179.36+0.36Minor7,480

The worst floods along the Rock River

For this gauge's highest crests, the other gauges on the Rock River that crested above flood stage within a week.

June 21, 2008: 13.51 ft here, major flooding

January 23, 2008: 12.21 ft here, major flooding

  • JoslinIL · Jan 30, 2008 · 13.76 ft · Minor

April 18, 2026: 12.11 ft here, moderate flooding

Gauges on the Rock River

Flood gauges sharing the river's name, linked within 80 miles of one another.

Flood gauges on the Rock River
Afton this gaugeWI9.013.51 ft, Jun 21, 20083
ByronIL13.017.80 ft, Apr 20, 19735
ComoIL12.515.64 ft, Jul 23, 20170
DixonIL16.020.50 ft, Apr 20, 19731
Fort AtkinsonWI16.020.90 ft, Jun 15, 20082
JeffersonWI10.015.64 ft, Jun 19, 20081
Lake KoshkonongWI10.015.13 ft, Jun 21, 20086
Latham ParkIL9.014.70 ft, Mar 26, 19753
Lebanon-3 E-Hwy MM bridgeWI10.014.01 ft, Jun 15, 20081
MolineIL12.016.53 ft, Apr 22, 201334
NewvilleWI6.58.51 ft, Apr 23, 20131
Rockford (Auburn Street)IL6.010.00 ft, Apr 20, 18811
Rockford (Fordam Dam)IL4.06.50 ft, Apr 20, 18811
RocktonIL10.015.54 ft, Mar 25, 19754
WatertownWI5.57.81 ft, Jun 13, 20082
JoslinIL12.019.24 ft, Jun 7, 200224

Other gauges in Rock County

Flood gauges in Rock County
Newville6.58.51 ft, Apr 23, 20131
Beloit7.513.00 ft, Apr 21, 19731
Beloit-3 NE9.014.20 ft, Apr 21, 19731
Clinton8.015.30 ft, Apr 21, 19732
Fulton10.012.07 ft, Jun 26, 20131

Rock County: every hazard · River floods across the country · Wisconsin

NOAA National Water Prediction Service, gauge AFTW3, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.