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Lake Michigan at Chicago (Chicago Lock)

Highest listed crest 5.98 ftFlood stage 4.0 ft28 crests since 1998

The Lake Michigan at Chicago (Chicago Lock) crested above flood stage 17 times among the 28 crests the National Weather Service lists from 1998 to 2020. The highest, 5.98 ft on April 29, 2020, was minor flooding, 1.98 feet above flood stage.

The gauge

Highest listed crest
5.98 ft
April 29, 2020
Flood stage
4.0 ft
Major flooding from 7.0 ft
Crests at major
0
17 above flood stage
Most recent flood crest
August 11, 2020
4.95 ft, minor flooding
Location
Cook County
Near Chicago (5.4 mi), Cicero (8.4 mi), Oak Park (9.4 mi)

Flood stages

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

Flood categories, Lake Michigan at Chicago (Chicago Lock)
Action stage2.59Dec 6, 2019The level at which the NWS or its partners begin to take action
Flood stage (minor)4.017Aug 11, 2020Minimal or no property damage, but possibly some public threat
Moderate flood stage6.00—Some inundation of structures and roads near the stream
Major flood stage7.00—Extensive inundation of structures and roads

Every listed crest

28 crests from 1998 to 2020. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Lake Michigan at Chicago (Chicago Lock), 1998 to 2020 234567ft Flood stage 4.0 ftMajor 7.0 ft May 31, 1998: 3.84 ft, action stageOct 31, 2014: 3.19 ft, action stageSep 19, 2015: 2.42 ft, below flood stageApr 8, 2016: 2.49 ft, below flood stageJul 12, 2017: 3.56 ft, action stageApr 14, 2018: 3.43 ft, action stageNov 26, 2018: 3.50 ft, action stageApr 14, 2019: 3.28 ft, action stageJun 1, 2019: 4.37 ft, minor floodingJul 20, 2019: 4.77 ft, minor floodingSep 5, 2019: 3.73 ft, action stageSep 11, 2019: 3.87 ft, action stageSep 28, 2019: 4.36 ft, minor floodingOct 2, 2019: 4.03 ft, minor floodingOct 16, 2019: 4.11 ft, minor floodingOct 26, 2019: 4.17 ft, minor floodingOct 31, 2019: 4.56 ft, minor floodingNov 11, 2019: 4.17 ft, minor floodingDec 1, 2019: 4.53 ft, minor floodingDec 6, 2019: 3.94 ft, action stageDec 29, 2019: 4.10 ft, minor floodingJan 11, 2020: 5.48 ft, minor floodingFeb 26, 2020: 4.28 ft, minor floodingMar 6, 2020: 4.64 ft, minor floodingApr 29, 2020: 5.98 ft, minor floodingJun 3, 2020: 5.07 ft, minor floodingJul 10, 2020: 4.14 ft, minor floodingAug 11, 2020: 4.95 ft, minor flooding Highest, 5.98 ft, Apr 29, 2020 20002005201020152020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Lake Michigan at Chicago (Chicago Lock) 1990s: 0 2000s: 0 2010s: 10 10 2020s: 7 1990s2000s2010s2020s
  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

Highest listed crests, Lake Michigan at Chicago (Chicago Lock)
1Apr 29, 20205.98+1.98Minor—
2Jan 11, 20205.48+1.48Minor—
3Jun 3, 20205.07+1.07Minor—
4Aug 11, 20204.95+0.95Minor—
5Jul 20, 20194.77+0.77Minor—
6Mar 6, 20204.64+0.64Minor—
7Oct 31, 20194.56+0.56Minor—
8Dec 1, 20194.53+0.53Minor—
9Jun 1, 20194.37+0.37Minor—
10Sep 28, 20194.36+0.36Minor—
11Feb 26, 20204.28+0.28Minor—
12Oct 26, 20194.17+0.17Minor—
13Nov 11, 20194.17+0.17Minor—
14Jul 10, 20204.14+0.14Minor—
15Oct 16, 20194.11+0.11Minor—
16Dec 29, 20194.10+0.10Minor—
17Oct 2, 20194.03+0.03Minor—
18Dec 6, 20193.94−0.06Action—
19Sep 11, 20193.87−0.13Action—
20May 31, 19983.84−0.16Action—
21Sep 5, 20193.73−0.27Action—
22Jul 12, 20173.56−0.44Action—
23Nov 26, 20183.50−0.50Action—
24Apr 14, 20183.43−0.57Action—
25Apr 14, 20193.28−0.72Action—
26Oct 31, 20143.19−0.81Action—
27Apr 8, 20162.49−1.51Below flood stage—
28Sep 19, 20152.42−1.58Below flood stage—

Other gauges in Cook County

Flood gauges in Cook County
Bellwood9.013.57 ft, Jul 24, 20104
Wheeling5.08.46 ft, Jun 26, 20136
Flossmoor9.013.08 ft, Apr 17, 20060
Markham10.012.00 ft, Oct 11, 19542
Chicago (Columbus Dr)3.05.50 ft, Oct 10, 19542
Chicago (Western Ave)4.05.26 ft, May 17, 20200
Chicago Heights10.012.87 ft, Sep 15, 20080
Des Plaines (Algonquin Road)13.021.00 ft, Sep 14, 20082
Lyons18.022.87 ft, Apr 18, 20132
River Forest16.018.98 ft, Apr 19, 20131
Riverside7.511.28 ft, Apr 18, 20137
Des Plaines15.020.92 ft, Apr 19, 20135
Lemont10.013.24 ft, May 18, 20200
Willow Springs10.010.57 ft, Apr 18, 20130
Lake Michigan at Calumet Harbor5.06.07 ft, Aug 11, 20200
Lansing7.010.18 ft, Oct 11, 19540
South Holland16.020.50 ft, Nov 28, 19905
Lemont6.011.10 ft, Jul 18, 19961
Mount Prospect5.08.08 ft, Aug 14, 19872
Oak Forest6.09.50 ft, Apr 5, 19472
Midlothian8.59.98 ft, Feb 2, 20160
Chicago (Grand Ave)3.05.70 ft, Oct 10, 19543
Chicago (Pulaski Rd)18.022.50 ft, Aug 14, 19871
Niles10.012.13 ft, Sep 14, 20082
Elgin5.57.69 ft, Sep 13, 20080
Elk Grove Village17.020.80 ft, May 18, 20200
Rolling Meadows8.514.03 ft, Aug 14, 19870
Western Springs7.510.65 ft, Apr 18, 20130
Worth31.036.50 ft, Oct 11, 19542
Glenwood8.511.14 ft, Jul 13, 19570
Thornton9.017.06 ft, Jun 14, 19816
Palos Park9.010.30 ft, Oct 10, 19540
Des Plaines9.015.09 ft, Jun 10, 19677
Northbrook7.010.10 ft, Aug 14, 19877

Cook County: every hazard · River floods across the country · Illinois

NOAA National Water Prediction Service, gauge LCRI2, 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.