National Weather Service United States Department of Commerce

Flood Categories changed on the Tidal Potomac River at Alexandria on August 15th


Effective on Wednesday, August 15th, 2018, some of the flood categories on the Tidal Potomac River at Alexandria were changed. This change is in response to recent analysis conducted by the City of Alexandria and is intended to better align impacts with the flood categories.

The NWS identifier for this gauge is AXTV2, and the gauge is operated by the United States Geological Survey (USGS).

The minor flood level at this location was raised from 3.1 feet to 3.3 feet. While only a small adjustment, this revision will allow for Coastal Flood Advisories to be issued only when nuisance-level impacts are observed, not at the first sign of water. Interests in the area should be advised that it is likely that some small amounts of water will be observed within the range between "action stage" of 2.5 feet and the new minor flood level of 3.3 feet.

The moderate flood level at this location was lowered from 4.5 feet to 4.2 feet. Collaboration with the City of Alexandria helped determine that, if not mitigated, structural flooding (which meets the moderate flood definition) occurs at 4.2 feet.

The following table summarizes the categories and changes:

Category Current Level New Level
Action Stage 2.5 feet 2.5 feet No change
Minor Flood 3.1 feet 3.3 feet Raised 0.2
Moderate Flood 4.5 feet 4.2 feet Lowered 0.3
Major Flood 6.6 feet 6.6 feet No change


To see the latest forecasts and observations for Alexandria, visit our Advanced Hydrologic Prediction Service website.