A prolific flooding event in the Washington, DC and Baltimore, MD region

Tropical air surged northwest from the Atlantic Ocean as a stationary front located over the Mid-Atlantic remained over the area between June 23 and June 27, 2006. The result was nearly five days of showers and thunderstorms across the Washington/Baltimore Region. Due to the tropical nature of the airmass, exceptionally heavy rain occurred in short periods of time. The high rain rates combined with scattered thunderstorms, which in a few cases reformed over the same areas, producing exceptionally heavy rainfall.

The entire region, from the Allegany Front and Potomac Highlands of the Appalachian Mountains, east to the Chesapeake Bay, had at least two inches of rainfall during this period. Five to ten inches was fairly common all across the Washington Metro Area. While Baltimore did not have quite as much rainfall as Washington, it was still excessive. Many of the Baltimore suburbs had more rain than either the Inner Harbor or Baltimore/Washington International Airport reporting stations. Eastern portions of the city had over 10 inches of rainfall during the period June 23 through June 27.

However, many places that experienced reforming and training thunderstorms had over ten inches of rainfall. The Delmarva had enhanced thunderstorm-induced rainfall conditions on June 24 and June 25th. Places like Federalsburg, Maryland had to be evacuated when over ten inches fell in only 24 hours. Washington DC and Columbia, Maryland had similar conditions on June 25th, when seven to ten inches of rain fell in only 24 hours. Northeast Maryland, just east and northeast of Baltimore, experienced extreme rainfall on June 25th, when seven to ten inches of rain fell in only 24 hours. One of the highest rainfall totals in the entire region was at North Bel Air, MD, just north of Baltimore, which had nearly 12 inches. Another maximum rainfall area was just west of Baltimore in the Laurel and Mount Airy areas, with around 10 inches.

Washington DC had several federal buildings closed, a mudslide occurred over the Capital Beltway, dozens of roads were closed, and cars were swept from parking garages and streets. Many swift water rescues were needed and dozens of buildings and homes were damaged and uninhabitable. Unfortunately, five people lost their lives to the ravages of flood waters during this flooding event.

New Washington National Airport records:

24 hour rainfall record: 7.94 inches

Record rainfall for one week: 11.20 inches

Record rainfall for a 2 day period: 9.41 inches

Daily rainfall record for Sunday, June 25:5.19 inches

Daily rainfall record for Monday, June 26:4.22 inches

First time more than four inches of rain fell on two consecutive days

Record rainfall for June: 14.02 inches

New Baltimore records at Baltimore/Washington International Airport:

Daily rainfall record for Sunday, June 25:2.75 inches

Few of Baltimore's official excessive precipitation records were exceeded by this event. These records were firmly set in August 1955, due to the remnants of Hurricanes Connie and Diane.

The photos are from Rock Creek Park in Washington, DC. These photos show displaced cars and extensive damages to roads, buildings, and other park areas. (All photos courtesy: National Park Service, Rock Creek Park staff.)

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