A potent upper-level low and associated area of surface low pressure approached the region from southwest on the 15th. Strong forcing for ascent and ample moisture transport in advance of the upper-level low led to a prolonged period of rain across the region. Eventually low pressure transferred to the coast before precipitation wound down on the 16th. Widespread rainfall totals of 2-4 inches were observed across the area.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 22:11:00 to 16-DEC-18 12:24:00 (EST-5)
Location: DARNESTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The stream gage on the Seneca Creek at Dawsonville exceeded the 7.5 foot flood stage during the indicated period, leading to flooding of the Seneca Creek Greenway, as well as a small portion of Berryville Road west of Darnestown. The peak level of 8.98 feet occurred at 1:35 AM on the 16th.

Flood in BALTIMORE, MARYLAND
From 16-DEC-18 03:10:00 to 16-DEC-18 08:28:00 (EST-5)
Location: GLENCOE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The stream gage on Gunpowder Falls at Glencoe exceeded the 7 foot flood stage during the indicated period. Flooding occurred along portions of Upper Glencoe Road and Lower Glencoe Road. The peak level of 7.76 feet occurred at 5:45 AM on December 16th.

Flood in ALLEGANY, MARYLAND
From 16-DEC-18 09:30:00 to 16-DEC-18 18:40:00 (EST-5)
Location: KEIFER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Potomac River at Paw Paw exceeded the 25 foot flood stage during the indicated period. The roadway to the C&O Canal parking area flooded, as did the lowest end of the Purslane Run hiker/biker area, and a parking area adjacent to the highway bridge. The peak level of 25.33 feet occurred at 1:00 PM.

Flood in MONTGOMERY, MARYLAND
From 17-DEC-18 00:09:00 to 18-DEC-18 06:24:00 (EST-5)
Location: GLEN ECHO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Potomac River at Little Falls exceeded the 10 foot flood stage during the indicated period. Water covered many locations along the C&O Canal towpath, and many hiking trails along the Potomac between Pennyfield Lock and Little Falls were closed as a result of the flooding. The peak level of 11.56 feet occurred at 1:00 PM on December 17th.

Flood in MONTGOMERY, MARYLAND
From 16-DEC-18 15:07:00 to 18-DEC-18 17:00:00 (EST-5)
Location: SENECA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Potomac River at Edwards Ferry exceeded the 15 foot flood stage during the indicated period. The basements at Edwards Ferry Lockhouse and Rileys Lockhouse were flooded. Backwater flooding affected homes on the Loudoun County side of the river near Broad Run in Sterling. Additionally, the parking lots at Edwards Ferry and Seneca were flooded, along with the store at Whites Ferry.  The peak level of 20.98 feet occurred at 9:00 AM on December 17th.

Flood in HOWARD, MARYLAND
From 16-DEC-18 02:00:00 to 16-DEC-18 11:31:00 (EST-5)
Location: ELKRIDGE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Patspsco River at Elkridge exceeded the 15 foot flood stage during the indicated period. Water covered a portion of River Road in Patapsco Valley State Park, and large portions of the park were flooded near the playground off Gunn Road. The peak level of 16.80 feet occurred at 5:50 AM on December 16th.

Flood in ANNE ARUNDEL, MARYLAND
From 15-DEC-18 20:41:00 to 16-DEC-18 09:36:00 (EST-5)
Location: MARYLAND CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Little Patuxent River at Savage exceeded the 10 foot flood stage during the indicated period. Riverside trails were flooded. Additionally, water approached Brock Bridge Road, as well as fields off of Bald Eagle Drive. The peak level of 12.27 feet occurred at 4:45 AM on December 16th.

Flood in FREDERICK, MARYLAND
From 16-DEC-18 16:08:00 to 18-DEC-18 04:55:00 (EST-5)
Location: TUSCARORA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Potomac River at Point of Rocks exceeded the 16 foot flood stage during the indicated period. Water covered the C&O towpath near Point of Rocks and Brunswick. Many low lying fields, as well as some boat launch ramps and parking lots, were also flooded.  The peak level of 22.40 feet occurred at 7:45 AM on December 17th.

Flood in FREDERICK, MARYLAND
From 16-DEC-18 09:37:00 to 17-DEC-18 02:03:00 (EST-5)
Location: GROVE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Monocacy River at Frederick exceeded the 15 foot flood stage during the indicated period, leading to flooding of portions of Pinecliff Park, as well as many of the low-lying fields at Monocacy National Battlefield. The peak level of 16.38 feet occurred at 8:45 PM on the 16th.

Flood in PRINCE GEORGE'S, MARYLAND
From 15-DEC-18 17:23:00 to 15-DEC-18 19:23:00 (EST-5)
Location: GLEN DALE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MD-564 closed at Duvall Street due to flooding.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 19:01:00 to 15-DEC-18 21:01:00 (EST-5)
Location: BRIGHTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Water rescue on Brighton Dam Road near Bordly Drive. Road closed, with 1.5 feet of water flowing across roadway.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 19:31:00 to 15-DEC-18 21:31:00 (EST-5)
Location: QUINCE ORCHARD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Riffle Ford Road was closed in both directions at Great Seneca Creek due to high water.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 20:19:00 to 15-DEC-18 22:19:00 (EST-5)
Location: BROOKEVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Georgia Avenue closed near Brookeville Road due to flooding.

Flood in MONTGOMERY, MARYLAND
From 16-DEC-18 06:30:00 to 16-DEC-18 08:30:00 (EST-5)
Location: BRIGHTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Brighton Dam Road closed due to flooding.

Flood in HOWARD, MARYLAND
From 16-DEC-18 11:39:00 to 16-DEC-18 13:39:00 (EST-5)
Location: SIMPSONVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Harriet Tubman Lane was closed due to flooding.

Flood in HOWARD, MARYLAND
From 16-DEC-18 11:41:00 to 16-DEC-18 13:41:00 (EST-5)
Location: ELKRIDGE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Furnace Avenue was closed due to flooding.

Flood in PRINCE GEORGE'S, MARYLAND
From 16-DEC-18 01:58:00 to 17-DEC-18 09:57:00 (EST-5)
Location: UPPER MARLBORO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The river gage on the Western Branch at Upper Marlboro exceeded the 11 foot flood stage during the indicated period. The Water Street bridge was completely covered by water and much of Race Track Road flooded between Marlboro Pike and the community center. The peak level of 13.44 feet occurred at 12:40 PM on December 16th.

Flood in HOWARD, MARYLAND
From 16-DEC-18 06:07:00 to 16-DEC-18 19:46:00 (EST-5)
Location: NORTH LAUREL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The stream gage on the Patuxent River below Duckett Dam near Laurel exceeded the 9.5 foot flood stage during the indicated period. Water overflowed the banks into nearby park land. The peak level of 9.65 feet occurred at 6:45 PM.

Flood in CARROLL, MARYLAND
From 16-DEC-18 00:58:00 to 16-DEC-18 05:31:00 (EST-5)
Location: KEYMAR
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The stream gage on the Big Pipe Creek at Bruceville exceeded the 8 foot flood stage during the indicated period. Keysville-Bruceville Road experienced flooding. The peak level of 8.78 feet occurred at 2:15 AM.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 23:19:00 to 16-DEC-18 01:35:00 (EST-5)
Location: KEMP MILL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The stream gage on the Northwest Branch of the Anacostia River at Colesville exceeded the 9 foot flood stage during the indicated period. Portions of the Northwest Branch Trail and Indian Spring Country Club, as well as backyards of homes on Kemps Mill Road just south of Randolph Road were flooded. The peak level of 9.25 feet occurred at 12:45 AM on the 16th.

Flood in MONTGOMERY, MARYLAND
From 15-DEC-18 19:28:00 to 15-DEC-18 21:28:00 (EST-5)
Location: UNITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Zion Road was closed in both direction at Gregg Road due to high water.