Potomac River near Washington DC (Little Falls)
Flood levels
Official flood levels at this gauge: action stage begins at 5.0 ft; minor flooding begins at 10.0 ft; moderate flooding begins at 12.0 ft; major flooding begins at 14.0 ft.
| Action stage | 5.0 ft |
|---|---|
| Minor flooding | 10.0 ft |
| Moderate flooding | 12.0 ft |
| Major flooding | 14.0 ft |
Highest recorded crests
- 28.1 ft on Mar 19, 1936 (historic crest)
- 26.9 ft on Oct 17, 1942 (historic crest)
- 23.3 ft on Apr 28, 1937 (historic crest)
- 22.0 ft on Jun 24, 1972 (historic crest)
What the water does
National Weather Service impact statements for this gauge, in the Weather Service's own words.
| 3.5 ft | The river reaches caution level for boaters, as defined by the State of Maryland. Fast moving water and changing currents will be experienced. |
|---|---|
| 4.5 ft | The river reaches danger level for boaters, as defined by the State of Maryland. Conditions for boating will be extremely hazardous. |
| 5.0 ft | Portions of the Potomac Heritage Trail begin to flood. Water begins to affect portions of the Billy Goat Trail between Great Falls and Carderock. These trails will be closed. |
| 5.5 ft | Water reaches the top of the ferry landing for Sycamore Island. Ferry service to the island will likely be suspended. |
| 7.0 ft | Upper portions of the River Trail at Great Falls National Park begin to flood and will be closed. |
| 9.0 ft | Several trails on both sides of the river between Great Falls and the Chain Bridge are flooded and will be closed. |
| 10.0 ft | Water begins to overflow the banks into low lying areas on the Maryland side of the river near Little Falls. Water begins to enter the canoe shed at Sycamore Island. |
| 11.0 ft | Water covers the towpath between Swains Lock and Pennyfield Lock, mileposts 17 to 19 on the C&O Canal. |
| 11.5 ft | Water covers the towpath in multiple spots between the Washington Aqueduct Dam and Pennyfield Lock, mileposts 15 to 19 on the C&O Canal. |
| 12.0 ft | The C&O Canal overflows at the Great Falls Tavern. Water covers the towpath in many areas. |
| 14.0 ft | Significant portions of the C&O Canal towpath are flooded. The Blockhouse Point Park is flooded. Water reaches the retaining wall at Overlook 1 at Great Falls National Park but does not overtop it. |
| 15.0 ft | Most of the C&O Canal towpath from Pennyfield downstream is flooded. |
| 16.0 ft | Water reaches the clubhouse on Sycamore Island. |
| 17.0 ft | Water overflows the overlooks at Great Falls National Park and approaches the lower level of the visitors center. Most of the C&O Canal towpath downstream of Pennyfield is flooded. There is approximately a foot of water in the clubhouse on Sycamore Island. |
Forecast office: NWS Sterling · River Forecast Center: Middle Atlantic River Forecast Center.
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