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Monongahela River at Grays Landing Lock and Dam

Highest listed crest 36.00 ftFlood stage 21.0 ft28 crests since 1888

The Monongahela River at Grays Landing Lock and Dam crested at major flood stage 3 times among the 28 crests the National Weather Service lists from 1888 to 2025. The highest, 36.00 ft on July 1, 1888, was major flooding, 15.00 feet above flood stage.

The gauge

Highest listed crest
36.00 ft
July 1, 1888
Flood stage
21.0 ft
Major flooding from 27.0 ft
Crests at major
3
68th of 170 gauges in Pennsylvania
Most recent flood crest
April 4, 2024
21.02 ft, minor flooding
Location
Greene County
Near Morgantown (13.0 mi)

Flood stages

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

Flood categories, Monongahela River at Grays Landing Lock and Dam
Action stage15.016May 31, 2025The level at which the NWS or its partners begin to take action
Flood stage (minor)21.08Apr 4, 2024Minimal or no property damage, but possibly some public threat
Moderate flood stage25.01Jan 20, 1996Some inundation of structures and roads near the stream
Major flood stage27.03Nov 5, 1985Extensive inundation of structures and roads

Every listed crest

28 crests from 1888 to 2025. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Monongahela River at Grays Landing Lock and Dam, 1888 to 2025 152025303540ft Flood stage 21.0 ftMajor 27.0 ft Jul 1, 1888: 36.00 ft, major floodingMar 18, 1936: 28.40 ft, major flooding; 130,000 cubic feet per secondNov 5, 1985: 30.50 ft, major flooding; 189,000 cubic feet per secondJan 20, 1996: 25.80 ft, moderate flooding; 147,000 cubic feet per secondFeb 19, 2000: 24.50 ft, minor flooding; 131,400 cubic feet per secondMar 21, 2002: 20.70 ft, action stage; 94,570 cubic feet per secondFeb 23, 2003: 19.00 ft, action stageMar 7, 2004: 19.34 ft, action stage; 77,000 cubic feet per secondApr 16, 2007: 19.31 ft, action stage; 76,820 cubic feet per secondDec 14, 2007: 21.70 ft, minor flooding; 105,808 cubic feet per secondJun 5, 2008: 19.27 ft, action stage; 76,270 cubic feet per secondMay 4, 2009: 21.00 ft, minor floodingJan 26, 2010: 20.60 ft, action stage; 90,303 cubic feet per secondNov 23, 2011: 20.09 ft, action stage; 86,800 cubic feet per secondMar 4, 2015: 22.78 ft, minor flooding; 116,735 cubic feet per secondMar 15, 2015: 18.51 ft, action stage; 66,860 cubic feet per secondJul 29, 2017: 23.95 ft, minor flooding; 139,200 cubic feet per secondJan 13, 2018: 18.70 ft, action stageFeb 17, 2018: 22.07 ft, minor floodingSep 10, 2018: 18.05 ft, action stage; 61,700 cubic feet per secondSep 28, 2018: 18.80 ft, action stage; 70,410 cubic feet per secondJan 20, 2019: 17.06 ft, action stageFeb 8, 2019: 16.85 ft, action stage; 49,450 cubic feet per secondFeb 13, 2019: 15.88 ft, action stage; 39,610 cubic feet per secondJul 1, 2019: 16.40 ft, action stage; 45,100 cubic feet per secondMar 1, 2021: 21.77 ft, minor flooding; 107,785 cubic feet per secondApr 4, 2024: 21.02 ft, minor flooding; 97,712 cubic feet per secondMay 31, 2025: 18.95 ft, action stage; 72,100 cubic feet per second Highest, 36.00 ft, Jul 1, 1888 1900192019401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Monongahela River at Grays Landing Lock and Dam 1880s: 1 1890s: 0 1900s: 0 1910s: 0 1920s: 0 1930s: 1 1940s: 0 1950s: 0 1960s: 0 1970s: 0 1980s: 1 1990s: 1 2000s: 3 3 2010s: 3 2020s: 2 1880s1900s1920s1940s1960s1980s2000s2020s
  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, Monongahela River at Grays Landing Lock and Dam
1Jul 1, 188836.00+15.00Major—
2Nov 5, 198530.50+9.50Major189,000
3Mar 18, 193628.40+7.40Major130,000
4Jan 20, 199625.80+4.80Moderate147,000
5Feb 19, 200024.50+3.50Minor131,400
6Jul 29, 201723.95+2.95Minor139,200
7Mar 4, 201522.78+1.78Minor116,735
8Feb 17, 201822.07+1.07Minor—
9Mar 1, 202121.77+0.77Minor107,785
10Dec 14, 200721.70+0.70Minor105,808
11Apr 4, 202421.02+0.02Minor97,712
12May 4, 200921.000.00Minor—
13Mar 21, 200220.70−0.30Action94,570
14Jan 26, 201020.60−0.40Action90,303
15Nov 23, 201120.09−0.91Action86,800
16Mar 7, 200419.34−1.66Action77,000
17Apr 16, 200719.31−1.69Action76,820
18Jun 5, 200819.27−1.73Action76,270
19Feb 23, 200319.00−2.00Action—
20May 31, 202518.95−2.05Action72,100
21Sep 28, 201818.80−2.20Action70,410
22Jan 13, 201818.70−2.30Action—
23Mar 15, 201518.51−2.49Action66,860
24Sep 10, 201818.05−2.95Action61,700
25Jan 20, 201917.06−3.94Action—
26Feb 8, 201916.85−4.15Action49,450
27Jul 1, 201916.40−4.60Action45,100
28Feb 13, 201915.88−5.12Action39,610

The worst floods along the Monongahela River

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

November 5, 1985: 30.50 ft here, major flooding

March 18, 1936: 28.40 ft here, major flooding

January 20, 1996: 25.80 ft here, moderate flooding

Gauges on the Monongahela River

In USGS station-number order, which runs downstream within a river basin.

Flood gauges on the Monongahela River
Morgantown Lock and DamWV22.027.70 ft, Nov 6, 19851
Point Marion Lock and Dam (lower pool)PA26.034.00 ft, Jan 19, 19967
Grays Landing Lock and Dam this gaugePA21.036.00 ft, Jul 1, 18883
Maxwell Lock and Dam (lower pool)PA32.044.40 ft, Nov 5, 19855
Charleroi Lock and DamPA28.042.70 ft, Nov 5, 198514
Elizabeth Lock and DamPA20.032.50 ft, Mar 18, 19369
Braddock Lock and DamPA22.035.30 ft, Mar 18, 19368

Other gauges in Greene County

Flood gauges in Greene County
Shannopin12.014.27 ft, Aug 18, 19800
Point Marion Lock and Dam (lower pool)26.034.00 ft, Jan 19, 19967
Jefferson17.018.96 ft, Sep 10, 20180

Greene County: every hazard · River floods across the country · Pennsylvania

NOAA National Water Prediction Service, gauge GYLP1, 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.