Flash Flooding and Winter Storm in Maryland, March 21 to 22, 2000

Name: Flash Flooding and Winter Storm in Maryland, March 21 to 22, 2000
Start: 2000-03-21T00:00
End: 2000-03-22T22:45
Location: Maryland

March 21 to 22, 2000 · NWS LWX · 15 events in 13 counties and zones

Low pressure moved from the Ohio Valley on the 20th to the Mid-Atlantic region on the 21st. East winds ahead of the system ushered moist air into the region directly from the Atlantic Ocean.

Where it happened

Every event with a place to put it; 14 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 15

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS LWX wrote it up.

Low pressure moved from the Ohio Valley on the 20th to the Mid-Atlantic region on the 21st. East winds ahead of the system ushered moist air into the region directly from the Atlantic Ocean. When the low passed through on the morning and afternoon of the 21st heavy rain fell east of the Blue Ridge Mountains. Temperatures were cold enough in Allegany County that most of the precipitation fell in the form of snow. Frostburg reported 6 inches of accumulation. Rainfall amounts in Washington County included 2.67 inches in Smithsburg, 2.43 inches in Hagerstown, 2.31 inches in Sharpsburg, 1.90 inches in Williamsport, and 1.80 inches in Hancock. The deluge of rain caused Beaver Creek to overflow onto Route 66 and Conococheague Creek to flood Wishard Road as it rose a half foot above flood stage. In Frederick County, rainfall totals included 3.30 inches in Thurmont, 2.55 inches in Emmitsburg, 2.10 inches in Wolfsville, and 2.05 inches in Frederick. Carroll Creek overflowed onto Gas House Pike and Israel Creek flooded Route 26. The Monocacy River near Frederick rose to 16.4 feet, nearly 1.5 feet above flood stage, on the 22nd causing flood waters to affect the sewage treatment plant. In Carroll County, rainfall amounts included 2.57 inches in Finksburg, 2.52 inches in Sykesville, 2.41 inches in Millers, 2.37 inches in Manchester, 2.28 inches at Piney Run, and 2.25 inches in Westminister. In Baltimore County, rainfall amounts included 3.16 inches in Pikesville, 2.77 inches in Owings Mills, 2.60 inches in Fullerton and Freeland, 2.31 inches in Parkton, 2.24 inches in Perry Hall, 2.16 inches in Cedermere, 2.04 inches in Freeland and Westview, 1.91 inches at the Maryland Science Center, 1.88 inches in Carroll Park, and 1.84 inches at Jones Falls. In Harford County, rainfall totals included 4.41 inches in Aberdeen, 3.95 inches at Conwingo Dam, and 2.55 inches in Bel Air. Little North East Creek, North Creek, and Swan Creek overflowed their banks. Rainfall totals for Howard and Montgomery Counties included 3.00 inches in Cooksville, 2.59 inches in Laurel, 2.52 inches in Gaithersburg, 2.46 inches in Waterloo and Olney, 2.44 inches in Lisbon, 2.40 inches in Washington Grove, 2.31 inches in Forest Glen, 2.30 inches in Potomac, 2.29 inches in Ellicott City, 2.00 inches in Elkridge, and 1.93 inches in Rockville. Rainfall amounts in Anne Arundel County included 3.69 inches in Annapolis, 3.00 inches at the Naval Academy, 2.26 inches in Lothian, 2.13 inches at Baltimore/Washington International Airport, 1.86 inches in Davidsonville, and 1.71 inches in Millersville. Heavy rain saturated soil to the point that trees were felled. Downed trees were reported on Generals Highway, Saltzmann Road, across the community of Cypress Creek, and on the campus of St. John's College. Flood waters closed parts of Patuxent Road, Brock Bridge Road, Ridge Road, Old Mill Road, and Governor's Bridge Road. Flooded roadways were also reported in Glen Isle, Avalon Shores, Franklin Manor, Shady Side, and Triton Beach. Rainfall totals in Prince George's County included 3.36 inches in Mitchellville, 3.12 inches at Brown Landfill, 2.96 inches in Bowie and District Heights, 2.88 inches in Greenbelt, 2.55 inches in South Bowie, 2.48 inches at Andrews Air Force Base, and 2.36 inches in Oxon Hill. Rainfall reports across Calvert, Charles, and St. Mary's Counties included 2.06 inches in Bryans Road, 2.04 inches in Ridge, 2.00 inches in Waldorf, and 1.36 inches in Tall Timbers.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

8 heavy rain, 4 flash flood, 2 flood, 1 winter storm. Local standard time, as filed.

Winter Storm, Allegany

When: March 21, 12:00 AM EST to 12:00 PM EST
Where: Allegany forecast zone
Reported by: TRAINED SPOTTER

Heavy Rain, Carroll

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Carroll County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.563, -77.022 (the zone’s center; the record gives no point)

Heavy Rain, Baltimore

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Baltimore County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.443, -76.616 (the zone’s center; the record gives no point)

Heavy Rain, Baltimore City (C)

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Baltimore City (C) County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.290, -76.612 (the zone’s center; the record gives no point)

Heavy Rain, Montgomery

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Montgomery County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.136, -77.204 (the zone’s center; the record gives no point)

Heavy Rain, Howard

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Howard County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.251, -76.931 (the zone’s center; the record gives no point)

Heavy Rain, Prince George'S

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Prince George'S County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 38.830, -76.847 (the zone’s center; the record gives no point)

Heavy Rain, Charles

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: Charles County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 38.474, -77.013 (the zone’s center; the record gives no point)

Heavy Rain, St. Mary'S

When: March 21, 8:00 AM EST to 4:00 PM EST
Where: St. Mary'S County, Countywide
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 38.216, -76.529 (the zone’s center; the record gives no point)

Flash Flood, Washington

When: March 21, 9:00 AM EST to 12:00 PM EST
Where: Washington County, Countywide
Reported by: TRAINED SPOTTER
Coordinates: 39.604, -77.814 (the zone’s center; the record gives no point)

Flash Flood, Frederick

When: March 21, 9:00 AM EST to 1:00 PM EST
Where: Frederick County, Countywide
Reported by: NEWSPAPER
Coordinates: 39.472, -77.398 (the zone’s center; the record gives no point)

Flash Flood, Anne Arundel

When: March 21, 5:00 PM EST to 11:59 PM EST
Where: Anne Arundel County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 38.994, -76.568 (the zone’s center; the record gives no point)

Flash Flood, Harford

When: March 21, 5:30 PM EST to 11:59 PM EST
Where: Harford County, Countywide
Reported by: TRAINED SPOTTER
Coordinates: 39.536, -76.299 (the zone’s center; the record gives no point)

Flood, Washington

When: March 22, 2:00 AM EST to 6:15 PM EST
Where: Washington forecast zone
Reported by: OFFICIAL NWS OBS.
Coordinates: 39.604, -77.814 (the zone’s center; the record gives no point)

Flood, Frederick

When: March 22, 8:45 AM EST to 10:45 PM EST
Where: Frederick forecast zone
Reported by: OFFICIAL NWS OBS.
Coordinates: 39.472, -77.398 (the zone’s center; the record gives no point)

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Maryland in 2000 Every state in 2000 This day in weather history Warnings in Maryland, March 2000

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5136809, 5136801, 5136802, 5136803, 5136804, 5136805, 5136806, 5136807, 5136808, 5136799, 5136800, 5136797, 5136798, 5136795, 5136796.