National Weather Service United States Department of Commerce

Minor Flood Level to change for Anne Arundel, Calvert, and Saint Mary's Counties

Solomons Island Pier
A picturesque look at the pier at the tip of Solomons Island, Maryland. The tide level in this area has been measured since 1937 and at this particular site since 1990. (NWS File Photo)


On May 15th, 2018, the defined minor flood level changed at tide gauges covering Anne Arundel, Calvert, and Saint Mary's counties in Maryland. For reference, the National Weather Service defines minor flooding as "minimal or no property damage, but possibly some public threat (e.g., inundation of roads)".  After analysis and discussion with local officials, it has been determined that while water may be observed on land at the current minor flood levels, no public threat occurs.  As a result, the minor flood level is being raised by a few inches at these locations to a level more likely to cause an impact/inconvenience to people. The change also ensures that issuance of a Coastal Flood Advisory occurs with a reasonably consistent impact at each sensitive location throughout the Baltimore/Washington area of responsibility.

The table below outlines the changes:

Minor Flood Level Changes - May 15, 2018
Based on Mean Lower Low Water (MLLW) datum
Location Current Minor Level New Minor Level
Annapolis, MD (APAM2) 2.4 ft MLLW 2.6 ft MLLW
North Beach, MD (NBCM2) 2.75 ft MLLW 3.0 ft MLLW
Solomons Island, MD (SLIM2) 2.75 ft MLLW 3.0 ft MLLW
Straits Point, MD (SGSM2) 2.7 ft MLLW 3.0 ft MLLW


For questions about these changes, please use the contact us link at the very bottom of this page.