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Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW)

Highest listed crest 9.77 ftFlood stage 3.4 ft31 crests since 1915

The Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW) crested at major flood stage 4 times among the 31 crests the National Weather Service lists from 1915 to 2025. The highest, 9.77 ft on August 13, 2025, was major flooding, 6.37 feet above flood stage.

The gauge

Highest listed crest
9.77 ft
August 13, 2025
Flood stage
3.4 ft
Major flooding from 6.0 ft
Crests at major
4
17th of 108 gauges in Maryland
Most recent flood crest
August 13, 2025
9.77 ft, major flooding
Location
Baltimore city
Near Baltimore (2.6 mi)
Identifiers
NWS BLTM2
No USGS station

Flood stages

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

Flood categories, Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW)
Action stage2.56Nov 10, 2017The level at which the NWS or its partners begin to take action
Flood stage (minor)3.411Apr 30, 2020Minimal or no property damage, but possibly some public threat
Moderate flood stage4.610May 28, 2025Some inundation of structures and roads near the stream
Major flood stage6.04Aug 13, 2025Extensive inundation of structures and roads

Every listed crest

31 crests from 1915 to 2025. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW), 1915 to 2025 246810ft Flood stage 3.4 ftMajor 6.0 ft Aug 4, 1915: 5.30 ft, moderate floodingAug 23, 1933: 7.69 ft, major floodingNov 25, 1950: 4.89 ft, moderate floodingSep 1, 1952: 4.69 ft, moderate floodingOct 15, 1954: 5.50 ft, moderate floodingAug 13, 1955: 6.39 ft, major floodingSep 6, 1979: 5.18 ft, moderate floodingNov 4, 1985: 5.13 ft, moderate floodingSep 7, 1996: 5.16 ft, moderate floodingSep 19, 2003: 8.15 ft, major floodingAug 15, 2017: 3.12 ft, action stageAug 31, 2017: 3.29 ft, action stageSep 20, 2017: 3.21 ft, action stageOct 14, 2017: 3.11 ft, action stageOct 24, 2017: 3.79 ft, minor floodingNov 5, 2017: 3.04 ft, action stageNov 10, 2017: 3.37 ft, action stageMar 7, 2018: 3.89 ft, minor floodingApr 16, 2018: 3.66 ft, minor floodingSep 9, 2018: 3.80 ft, minor floodingSep 21, 2018: 3.85 ft, minor floodingNov 27, 2018: 3.66 ft, minor floodingDec 21, 2018: 3.49 ft, minor floodingOct 12, 2019: 4.16 ft, minor floodingNov 19, 2019: 3.61 ft, minor floodingApr 13, 2020: 4.17 ft, minor floodingApr 30, 2020: 4.24 ft, minor floodingOct 30, 2021: 4.92 ft, moderate floodingDec 16, 2022: 5.31 ft, moderate floodingMay 28, 2025: 5.85 ft, moderate floodingAug 13, 2025: 9.77 ft, major flooding Highest, 9.77 ft, Aug 13, 2025 192019401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW) 1910s: 1 1920s: 0 1930s: 1 1940s: 0 1950s: 4 1960s: 0 1970s: 1 1980s: 1 1990s: 1 2000s: 1 2010s: 9 9 2020s: 6 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

Highest listed crests, Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW)
1Aug 13, 20259.77+6.37Major—
2Sep 19, 20038.15+4.75Major—
3Aug 23, 19337.69+4.29Major—
4Aug 13, 19556.39+2.99Major—
5May 28, 20255.85+2.45Moderate—
6Oct 15, 19545.50+2.10Moderate—
7Dec 16, 20225.31+1.91Moderate—
8Aug 4, 19155.30+1.90Moderate—
9Sep 6, 19795.18+1.78Moderate—
10Sep 7, 19965.16+1.76Moderate—
11Nov 4, 19855.13+1.73Moderate—
12Oct 30, 20214.92+1.52Moderate—
13Nov 25, 19504.89+1.49Moderate—
14Sep 1, 19524.69+1.29Moderate—
15Apr 30, 20204.24+0.84Minor—
16Apr 13, 20204.17+0.77Minor—
17Oct 12, 20194.16+0.76Minor—
18Mar 7, 20183.89+0.49Minor—
19Sep 21, 20183.85+0.45Minor—
20Sep 9, 20183.80+0.40Minor—
21Oct 24, 20173.79+0.39Minor—
22Apr 16, 20183.66+0.26Minor—
23Nov 27, 20183.66+0.26Minor—
24Nov 19, 20193.61+0.21Minor—
25Dec 21, 20183.49+0.09Minor—
26Nov 10, 20173.37−0.03Action—
27Aug 31, 20173.29−0.11Action—
28Sep 20, 20173.21−0.19Action—
29Aug 15, 20173.12−0.28Action—
30Oct 14, 20173.11−0.29Action—
31Nov 5, 20173.04−0.36Action—

Other gauges in Baltimore city

Flood gauges in Baltimore city
Washington Blvd in Baltimore13.020.03 ft, Aug 26, 19990
Baltimore Harbor3.04.14 ft, Oct 12, 20190

Baltimore city: every hazard · River floods across the country · Maryland

NOAA National Water Prediction Service, gauge BLTM2, 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.