Highest listed crest 18.74 ft June 8, 2008; 13,100 cubic feet per second
Flood stage 10.0 ft Major flooding from 15.5 ft
Crests at major 2 70th of 203 gauges in Iowa
Most recent flood crest August 19, 2025 11.19 ft, minor flooding Listed crests at the Winnebago River at Mason City, 1933 to 2025 0 5 10 15 20 ft Flood stage 10.0 ft Major 15.5 ft Mar 30, 1933: 15.70 ft, major flooding; 10,800 cubic feet per second Apr 3, 1934: 4.10 ft, below flood stage; 1,470 cubic feet per second Mar 5, 1935: 5.80 ft, below flood stage; 2,340 cubic feet per second Mar 16, 1936: 6.10 ft, below flood stage; 2,520 cubic feet per second Mar 5, 1937: 9.68 ft, action stage; 5,260 cubic feet per second Jun 25, 1938: 10.29 ft, minor flooding; 5,850 cubic feet per second Mar 13, 1939: 7.90 ft, below flood stage; 3,730 cubic feet per second Mar 29, 1940: 3.40 ft, below flood stage; 980 cubic feet per second Jun 2, 1941: 4.40 ft, below flood stage; 1,500 cubic feet per second Nov 1, 1941: 5.80 ft, below flood stage; 2,290 cubic feet per second Mar 16, 1943: 7.93 ft, below flood stage; 3,760 cubic feet per second Jun 12, 1944: 12.20 ft, minor flooding; 7,020 cubic feet per second Mar 11, 1945: 10.22 ft, minor flooding; 4,600 cubic feet per second Mar 14, 1946: 6.90 ft, below flood stage; 2,970 cubic feet per second Jun 30, 1947: 8.80 ft, action stage; 4,360 cubic feet per second Feb 28, 1948: 11.22 ft, minor flooding; 5,000 cubic feet per second Mar 4, 1949: 7.40 ft, below flood stage; 3,310 cubic feet per second Mar 7, 1950: 7.30 ft, below flood stage; 3,310 cubic feet per second Apr 7, 1951: 12.44 ft, minor flooding; 7,560 cubic feet per second Mar 30, 1952: 8.70 ft, action stage; 4,360 cubic feet per second Aug 3, 1953: 4.73 ft, below flood stage; 1,730 cubic feet per second Jun 21, 1954: 11.85 ft, minor flooding; 7,060 cubic feet per second Jun 3, 1955: 5.75 ft, below flood stage; 2,330 cubic feet per second Apr 1, 1956: 4.15 ft, below flood stage; 1,360 cubic feet per second May 30, 1957: 3.58 ft, below flood stage; 1,090 cubic feet per second Jun 4, 1958: 3.83 ft, below flood stage; 955 cubic feet per second May 21, 1959: 7.33 ft, below flood stage; 3,040 cubic feet per second Mar 28, 1960: 5.98 ft, below flood stage; 2,320 cubic feet per second Mar 27, 1961: 14.80 ft, moderate flooding; 10,500 cubic feet per second Aug 31, 1962: 13.06 ft, minor flooding; 8,510 cubic feet per second Jul 19, 1963: 8.86 ft, action stage; 4,120 cubic feet per second Sep 9, 1964: 4.85 ft, below flood stage; 1,620 cubic feet per second Apr 11, 1965: 14.27 ft, minor flooding; 9,700 cubic feet per second Feb 9, 1966: 8.52 ft, action stage; 2,300 cubic feet per second Jun 10, 1967: 6.00 ft, below flood stage; 1,400 cubic feet per second Jun 27, 1968: 7.30 ft, below flood stage; 2,370 cubic feet per second Jul 8, 1969: 12.25 ft, minor flooding; 6,850 cubic feet per second May 30, 1970: 6.84 ft, below flood stage; 2,030 cubic feet per second Apr 1, 1971: 8.24 ft, action stage; 3,150 cubic feet per second Sep 28, 1972: 6.65 ft, below flood stage; 1,890 cubic feet per second Mar 11, 1973: 9.37 ft, action stage; 3,700 cubic feet per second Mar 3, 1974: 7.26 ft, below flood stage; 2,100 cubic feet per second Apr 28, 1975: 10.48 ft, minor flooding; 5,130 cubic feet per second Mar 12, 1976: 9.00 ft, action stage; 3,100 cubic feet per second May 5, 1977: 4.26 ft, below flood stage; 360 cubic feet per second Jun 15, 1978: 7.36 ft, below flood stage; 2,430 cubic feet per second Aug 23, 1979: 11.33 ft, minor flooding; 5,930 cubic feet per second May 30, 1980: 11.66 ft, minor flooding; 6,250 cubic feet per second Jun 24, 1981: 10.90 ft, minor flooding; 5,510 cubic feet per second Jun 7, 1982: 9.16 ft, action stage; 3,940 cubic feet per second Mar 7, 1983: 8.88 ft, action stage; 3,690 cubic feet per second Jun 8, 1984: 11.94 ft, minor flooding; 6,540 cubic feet per second Mar 11, 1985: 6.48 ft, below flood stage; 1,700 cubic feet per second Mar 18, 1986: 9.40 ft, action stage; 4,200 cubic feet per second Apr 29, 1988: 4.67 ft, below flood stage; 607 cubic feet per second Mar 11, 1989: 5.30 ft, below flood stage; 929 cubic feet per second Aug 25, 1990: 7.86 ft, below flood stage; 2,830 cubic feet per second May 18, 1991: 11.58 ft, minor flooding; 5,630 cubic feet per second Mar 9, 1992: 8.25 ft, action stage; 3,150 cubic feet per second Apr 1, 1993: 12.59 ft, minor flooding; 7,190 cubic feet per second Jul 16, 1994: 7.26 ft, below flood stage; 2,330 cubic feet per second Jun 7, 1995: 6.81 ft, below flood stage; 1,980 cubic feet per second Mar 25, 1996: 6.34 ft, below flood stage; 1,270 cubic feet per second Mar 11, 1997: 9.32 ft, action stage; 3,640 cubic feet per second Jun 24, 1998: 8.01 ft, action stage; 2,750 cubic feet per second Jul 21, 1999: 11.84 ft, minor flooding; 6,100 cubic feet per second Jun 16, 2000: 6.76 ft, below flood stage; 2,020 cubic feet per second Apr 12, 2001: 11.83 ft, minor flooding; 6,430 cubic feet per second Aug 6, 2002: 6.92 ft, below flood stage; 2,120 cubic feet per second May 11, 2003: 6.84 ft, below flood stage; 2,060 cubic feet per second May 22, 2004: 14.67 ft, moderate flooding; 9,990 cubic feet per second Apr 19, 2005: 10.84 ft, minor flooding; 5,610 cubic feet per second Apr 3, 2006: 7.06 ft, below flood stage; 2,370 cubic feet per second Mar 15, 2007: 9.47 ft, action stage; 4,270 cubic feet per second Jun 8, 2008: 18.74 ft, major flooding; 13,100 cubic feet per second Feb 11, 2009: 6.74 ft, below flood stage; 2,180 cubic feet per second Mar 12, 2010: 11.20 ft, minor flooding; 6,380 cubic feet per second Mar 23, 2011: 7.55 ft, below flood stage; 3,110 cubic feet per second May 6, 2012: 5.47 ft, below flood stage; 1,320 cubic feet per second May 20, 2013: 9.44 ft, action stage Jun 20, 2014: 9.36 ft, action stage; 4,890 cubic feet per second Jun 22, 2015: 7.10 ft, below flood stage; 2,800 cubic feet per second Sep 22, 2016: 14.07 ft, minor flooding Feb 21, 2017: 7.14 ft, below flood stage; 2,750 cubic feet per second Sep 21, 2018: 12.17 ft, minor flooding; 7,240 cubic feet per second Mar 17, 2019: 10.54 ft, minor flooding Oct 6, 2019: 7.27 ft, below flood stage; 2,860 cubic feet per second Mar 5, 2020: 7.34 ft, below flood stage Aug 28, 2021: 5.78 ft, below flood stage; 1,570 cubic feet per second Apr 13, 2022: 10.91 ft, minor flooding; 4,160 cubic feet per second Feb 27, 2023: 11.24 ft, minor flooding Jun 22, 2024: 10.98 ft, minor flooding; 4,190 cubic feet per second Aug 19, 2025: 11.19 ft, minor flooding; 4,520 cubic feet per second Highest, 18.74 ft, Jun 8, 2008 1940 1960 1980 2000 2020 Crests at or above flood stage, by decade Crests at or above flood stage per decade, Winnebago River at Mason City 1930s: 2 1940s: 3 1950s: 2 1960s: 4 4 1970s: 2 1980s: 3 1990s: 3 2000s: 4 2010s: 4 2020s: 4 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 2020s 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. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable. Cerro Gordo County: every hazard · River floods across the country · Iowa
NOAA National Water Prediction Service, gauge MCWI4, 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.