Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW)
Stage at this gauge is reported IN MLLW.
Flood levels
Official flood levels at this gauge: action stage begins at 2.5 ft; minor flooding begins at 3.4 ft; moderate flooding begins at 4.6 ft; major flooding begins at 6.0 ft.
| Action stage | 2.5 ft |
|---|---|
| Minor flooding | 3.4 ft |
| Moderate flooding | 4.6 ft |
| Major flooding | 6.0 ft |
Highest recorded crests
- 9.8 ft on Aug 13, 2025 (historic crest)
- 8.2 ft on Sep 19, 2003 (historic crest)
- 7.7 ft on Aug 23, 1933 (historic crest)
- 6.4 ft on Aug 13, 1955 (historic crest)
What the water does
National Weather Service impact statements for this gauge, in the Weather Service's own words.
| 2.0 ft | Water begins to cover the lower promenade at the Harbor Place water taxi stop. |
|---|---|
| 3.0 ft | Flooding is occurring at the end of Thames Street. Water also nearly covers the promenade at the dragon boat dock in the Inner Harbor. |
| 3.5 ft | Water begins to cover the promenade at the Inner Harbor at the electric boat dock west of the World Trade Center. A half foot of water covers parts of Thames Street in the Fells Point area. |
| 4.2 ft | The concrete promenade at Fells Point begins to flood. Water also begins to cover the boardwalk at the Maritime Park water taxi stop. |
| 4.5 ft | The end of Ann Street begins to flood. |
| 5.0 ft | Water begins to cover the Pier 4 promenade on the east side. |
| 5.2 ft | The boardwalk at Fells Point begins to flood. Water also begins to cover low spots in the promenade at the end of Broadway Street. |
| 5.5 ft | Water begins to cover the Pier 4 promenade on the west side and Pier 5 on the west side. |
| 6.0 ft | Water reaches the corner of Ann Street and Thames Street. |
| 6.5 ft | Water approaches Caroline Street. |
Forecast office: NWS Sterling · River Forecast Center: Middle Atlantic River Forecast Center.
A NOAA tide station shares this spot: Baltimore, with tide predictions and official flood levels.
Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW) in your pocket
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Nearby stations and gauges
- Baltimore NOAA tide station · 0.2 mi
- Fort McHenry Marsh NOAA tide station · 0.6 mi
- Unnamed Tributary at Harbor Point in Baltimore NWS gauge · 1.3 mi
- Jones Falls at Baltimore Harbor NWS gauge · 1.6 mi
- Gwynns Falls at Annapolis Road in Baltimore NWS gauge · 2.7 mi
- at Herring Run at Route 40 in Baltimore NWS gauge · 3.3 mi