Event extended (time). Flood Warning from 9/24/2021 1:50 AM to 5:00 PM EDT for Central Maryland. More information.
Interactive NWS Alert
Radar valid at 500 pm EDT, Sep 24th 2021
...Forecast flooding changed from Minor to Moderate severity and
increased in duration for the following rivers in Maryland...
Monocacy River near Frederick affecting Frederick County.
For the Monocacy River...including Frederick...Moderate flooding is
150 AM EDT Fri Sep 24 2021
...Forecast flooding increased from Minor to Moderate severity and
increased in duration until late this afternoon...
The Flood Warning continues for
the Monocacy River near Frederick.
* Until late this afternoon.
* At 1:30 AM EDT Friday the stage was 18.5 feet, or 3.5 feet above
* Flood stage is 15.0 feet.
* Moderate flooding is occurring and moderate flooding is forecast.
* Recent Activity...The maximum river stage in the 24 hours ending
at 1:30 AM EDT Friday was 18.5 feet.
* Forecast...The river is expected to rise to a crest of 18.6 feet
early this morning. It will then fall below flood stage late this
* Impact...At 17.0 feet, significant lowland flooding is occurring
along the river, with backwater flooding also occurring. Numerous
roads are closed. Water is approaching the parking lot at Gambrill
Mill on the Monocacy National Battlefield. Backwater flooding from
Carroll Creek is likely approaching the underside of the bridge
leading to the Frederick city wastewater treatment plant.
* Flood History...This crest compares to a previous crest of 18.5
feet on 05/19/1988.
River Name Fld Observed Fri Fri Fri Crest
Location Stg Stg Day/Time 8AM 2PM 8PM Stg Time Date
Frederick 15.0 18.5 Fri 1 am 18.2 12.1 10.1 18.6 5am Fri
LAT...LON 3958 7738 3955 7731 3940 7735 3924 7741
3922 7745 3926 7748 3951 7742
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