Flash Flood — Frederick, Maryland

2025-07-31 · near New Market, Frederick, Maryland

Event narrative

Six inches of water over the roadway near the Monrovia Park and Ride along Green Valley Road.

Wider weather episode

A slow moving cold front combined with a highly unstable atmosphere along with tropical moisture to produce slow moving thunderstorms with heavy rainfall. Some of these storms trained over the same areas, resulting in scattered to numerous instances of flash flooding. Total rainfall amounts in areas with flash flooding averaged two to four inches, though some localized amounts up to six inches were observed.

View location on OpenStreetMap → (39.3800, -77.2600)

Source: NOAA Storm Events Database, event_id 1270202. Narrative written by the NWS forecast office that issued the report.