A cold front slowly sagged southward through Pennsylvania during the afternoon hours of May 15th. A line of storms spread ahead of this front, causing a widespread 1-3 inches of rain across North Central and Northeast Maryland. The western end of this line stalled, producing 3-6 inches of rain in a relatively short period of time in Frederick and extreme southeastern Washington Counties, prompting numerous water rescues and causing somewhat significant damage. The front stalled, and the next evening (May 16th), a second round of extreme rainfall struck much of the same area, with 3-6 inches of rain observed again in Frederick and southeastern Washington Counties. Renewed flooding ensued which continued into the morning hours of May 17th.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 19:50:00 to 15-MAY-18 21:00:00 (EST-5)
Location: ROSEMONT
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

The road surface and bridge were partially washed out on Maryland Route 180 at Little Catoctin Creek. The stream gage at this location was damaged.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 20:04:00 to 15-MAY-18 20:45:00 (EST-5)
Location: AUGUSTA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A swift water rescue was reported on Rohrersville Road near Brownsville.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 20:15:00 to 15-MAY-18 21:00:00 (EST-5)
Location: SANDY HOOK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

Runoff from heavy rain caused a rock slide across Back Road near Harpers Ferry Road.

Flood in ANNE ARUNDEL, MARYLAND
From 15-MAY-18 21:14:00 to 15-MAY-18 23:00:00 (EST-5)
Location: NORTH LINTHICUM
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Nursery Road was flooded and closed at Holly Creek near Pumphrey.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 20:48:00 to 15-MAY-18 21:30:00 (EST-5)
Location: DARGAN
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

Water reportedly entered a home in the 2300 block of Chestnut Grove Road.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 20:35:00 to 15-MAY-18 21:00:00 (EST-5)
Location: FEAGAVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Jefferson Pike (Maryland Route 180) flooded and closed at the Ballenger Creek bridge.

Flood in FREDERICK, MARYLAND
From 15-MAY-18 21:00:00 to 15-MAY-18 22:00:00 (EST-5)
Location: CATOCTIN STATION
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

A portion of the C and O Canal towpath was washed out near mile marker 52.5.

Flood in ANNE ARUNDEL, MARYLAND
From 15-MAY-18 21:20:00 to 15-MAY-18 23:00:00 (EST-5)
Location: BESTGATE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Defense Highway was flooded and closed at Broad Creek near Parole.

Flood in FREDERICK, MARYLAND
From 15-MAY-18 21:25:00 to 15-MAY-18 23:00:00 (EST-5)
Location: CATOCTIN STATION
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A passenger train was surrounded by floodwaters as it moved westward between Point of Rocks and Brunswick. Water never entered the train but eyewitnesses reported water up to the bottom step and partial undermining of the tracks.

Flood in WASHINGTON, MARYLAND
From 15-MAY-18 23:00:00 to 16-MAY-18 02:00:00 (EST-5)
Location: SANDY HOOK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Ongoing flooding throughout the overnight hours following torrential rains in South Washington County. Several roads remained covered by water and closed.

Flood in FREDERICK, MARYLAND
From 16-MAY-18 16:53:00 to 16-MAY-18 23:00:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

High standing water was covering North Market Street at Schifferstadt Boulevard. The road was closed as a result.

Flood in FREDERICK, MARYLAND
From 16-MAY-18 17:25:00 to 16-MAY-18 20:00:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

For the second day in a row, flooding occurred near North Market Street and 9th Street. Water was reported to be entering garages in the area, and covering yards.

Flood in FREDERICK, MARYLAND
From 16-MAY-18 20:50:00 to 17-MAY-18 04:00:00 (EST-5)
Location: HARMONY GROVE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Widespread flooding occurred throughout southern Frederick County for the second day in a row.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 19:40:00 to 15-MAY-18 20:40:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 43.20M
Crop damage: 0.00K
Reported by: Emergency Manager

Significant flash flooding occurred during the evening of May 15th from the city of Frederick southwestward toward Braddock Heights and Jefferson. The amount of damage shown here is total damage not already accounted for in other reports.

Flood in FREDERICK, MARYLAND
From 17-MAY-18 04:30:00 to 17-MAY-18 05:30:00 (EST-5)
Location: HARMONY GROVE
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Two water rescues near the intersection of Willow Road and Willowbrook Road along Tuscarora Creek. Water was up to the hoods of the vehicles.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 19:25:00 to 15-MAY-18 21:00:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

High water rapidly flowing across Market Street and Schifferstadt Boulevard north of downtown Frederick.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 19:49:00 to 15-MAY-18 21:00:00 (EST-5)
Location: DARGAN
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A home on Mount Lock Canal Road was flooded. The occupants were rescued.

Flood in FREDERICK, MARYLAND
From 15-MAY-18 18:32:00 to 15-MAY-18 19:25:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Heavy rain flooded and closed Market Street near Schifferstadt Boulevard.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 19:45:00 to 15-MAY-18 21:00:00 (EST-5)
Location: FT DETRICK
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Newspaper

Floodwaters were more than two feet deep on North Market Street near the Frederick YMCA. Water entered buildings in the area and several parked cars were mostly submerged in water. The YMCA building itself had water enter the building with an estimated 40,000 sqft of the 95,000 sqft facility suffering water damage.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 19:13:00 to 15-MAY-18 21:00:00 (EST-5)
Location: FREDERICK
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Social Media

Flowing water up over the curb in downtown Frederick on Market Street. Water entered several businesses on Patrick Street. One business reported water at least two feet deep.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 21:44:00 to 15-MAY-18 22:15:00 (EST-5)
Location: AUGUSTA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Two people were rescued from a home with floodwaters inundating it near Brownsville.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 20:13:00 to 15-MAY-18 21:00:00 (EST-5)
Location: JEFFERSON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

US 340 Westbound flooded and closed west of Jefferson.

Flash Flood in WASHINGTON, MARYLAND
From 15-MAY-18 19:40:00 to 15-MAY-18 21:00:00 (EST-5)
Location: GAPLAND
Flood cause: Heavy Rain
Property damage: 4.60M
Crop damage: 0.00K
Reported by: 911 Call Center

Widespread and significant flooding ongoing throughout Southeastern Washington County as a result of torrential rainfall. Numerous roads closed, water rescues ongoing, partial washouts of roads, and water inside homes.

Flash Flood in FREDERICK, MARYLAND
From 15-MAY-18 20:01:00 to 15-MAY-18 21:00:00 (EST-5)
Location: FREDERICK
Flood cause: Heavy Rain
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Social Media

Flooding was reported on the west side of Frederick with vehicles floating in the parking lot of businesses along portions of the Golden Mile area.