Event extended (time). Flood Warning from 9/23/2021 9:46 PM to 9/24/2021 11:00 AM EDT for Central Maryland. More information.
Interactive NWS Alert
Radar valid at 1100 am EDT, Sep 24th 2021
...Observed 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
946 PM EDT Thu Sep 23 2021
...Observed flooding increased from Minor to Moderate severity and
increased in duration until late tomorrow morning...
The Flood Warning continues for
the Monocacy River near Frederick.
* Until late tomorrow morning.
* At 9:16 PM EDT Thursday the stage was 17.6 feet, or 2.6 feet above
* Flood stage is 15.0 feet.
* Moderate flooding is occurring and minor flooding is forecast.
* Recent Activity...The maximum river stage in the 24 hours ending
at 9:16 PM EDT Thursday was 17.6 feet.
* Forecast...The river is expected to fall below flood stage late
tonight and continue falling to 5.0 feet Sunday evening.
* 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 17.5
feet on 04/21/1940.
River Name Fld Observed Fri Fri Fri Crest
Location Stg Stg Day/Time 2AM 8AM 2PM Stg Time Date
Frederick 15.0 17.6 Thu 9 pm 16.5 14.1 11.9 17.8 Thu 10 pm
LAT...LON 3958 7738 3955 7731 3940 7735 3924 7741
3922 7745 3926 7748 3951 7742
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