Tropical Storm and Flash Flooding in Maryland, September 6, 2008

Name: Tropical Storm and Flash Flooding in Maryland, September 6, 2008
Start: 2008-09-06T11:44
End: 2008-09-06T18:30
Location: Maryland

September 6, 2008 · NWS LWX · 10 events in 6 counties and zones

Where it happened

Every event with a place to put it; 2 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 10

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.

Tropical Storm Hanna tracked up the Mid-Atlantic coast on the 6th with maximum sustained winds around 50 mph. Hanna originally made landfall near the border of North and South Carolina around 3:20 AM on the 6th. Hanna tracked across eastern North Carolina during the early afternoon hours before turning northeast across southeastern Virginia later in the afternoon. Hanna eventually tracked across the Chesapeake Bay and into Delaware during the evening hours. With the track of Hanna being to the east, the strongest winds were also confined to our east. However, Hanna was still responsible for heavy rain along with Tropical Storm force winds across Maryland. Rainfall amounts totaled around 4 to 8 inches across many locations. Numerous roads were closed throughout Maryland due to flash flooding. Tropical Storm force winds were responsible for downed trees and power lines across Maryland as well. The worst conditions occurred during the late morning and afternoon hours as the storm passed by just to the east.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Baltimore/Washington wrote its last area forecast discussion before the first event at Sep 6, 10:40 AM EST, 1 hour 4 minutes earlier.

Area forecast discussion, Sep 6, 10:40 AM EST, 1 hour 4 minutes before

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Hazardous weather outlook, Sep 6, 10:22 AM EST, 1 hour 22 minutes before

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In the hours before

Local storm report, Sep 6, 7:34 AM EST, 4 hours 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
834 AM EDT SAT SEP 06 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 AM     TROPICAL STORM   2 SW FABER              37.81N 78.76W
09/06/2008                   NELSON             VA   TRAINED SPOTTER

            1 TREE DOWN OVER LAUREL RD.

&&

CSTRONG

Local storm report, Sep 6, 9:17 AM EST, 2 hours 27 minutes before

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Local storm report, Sep 6, 10:44 AM EST, 1 hour before

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Local storm report, Sep 6, 11:26 AM EST, 18 minutes before

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Local storm report, Sep 6, 11:30 AM EST, 14 minutes before

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Local storm report, Sep 6, 11:44 AM EST, 0 minutes before

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The radar

The Dover AFB radar (KDOX), 116 km away, was scanning. The volume nearest the first event began at 17:43 UTC.

Open the radar archive at this moment

Event by event

5 tropical storm, 4 flash flood, 1 flood. Local standard time, as filed.

Tropical Storm, St. Mary'S

When: September 6, 11:44 AM EST
Where: St. Mary'S forecast zone
Reported by: Emergency Manager
Coordinates: 38.216, -76.529 (the zone’s center; the record gives no point)

Trees were down in Ridge.

Flash Flood, Montgomery

When: September 6, 12:45 PM EST to 5:10 PM EST
Where: Montgomery County, 0.23 mi ENE of Parkside to 0.74 mi ENE of Homewood
Cause: Heavy Rain / Tropical System
Reported by: Amateur Radio
Coordinates: 39.031, -77.076

Kensington Road at Beach Road was closed due to flash flooding. Beach Drive and Sligo Creek Parkway were also shut down due to flash flooding.

Tropical Storm, Howard

When: September 6, 1:00 PM EST
Where: Howard forecast zone
Reported by: Broadcast Media

Trees were down across Columbia, Maryland. One of the trees fell on a vehicle.

Flash Flood, Frederick

When: September 6, 1:00 PM EST to 5:00 PM EST
Where: Frederick County, 0.97 mi SW of Hansonville to 1.26 mi E of Walkersville
Cause: Heavy Rain / Tropical System
Reported by: Newspaper
Coordinates: 39.490, -77.432

Roads were closed around Frederick due to flash flooding.

Tropical Storm, Montgomery

When: September 6, 1:45 PM EST
Where: Montgomery forecast zone
Reported by: Broadcast Media

A tree was down on Interstate 270 near Montrose road in Germantown, Maryland.

Tropical Storm, Frederick

When: September 6, 2:00 PM EST
Where: Frederick forecast zone
Reported by: Newspaper
Coordinates: 39.472, -77.398 (the zone’s center; the record gives no point)

A large tree was down between U.S. 15 southbound and Point of Rocks road.

Flash Flood, Carroll

When: September 6, 2:30 PM EST to 5:00 PM EST
Where: Carroll County, 2.15 mi SSE of Mc Kinstrys to 2.16 mi SSE of Mc Kinstrys
Cause: Heavy Rain / Tropical System
Reported by: Emergency Manager
Coordinates: 39.524, -77.148

Sams Creek Road near the county line was closed due to flash flooding.

Tropical Storm, Harford

When: September 6, 3:30 PM EST
Where: Harford forecast zone
Reported by: Fire Department/Rescue

Eight roads were closed due to trees down in Harford county.

Flash Flood, Harford

When: September 6, 4:30 PM EST to 6:30 PM EST
Where: Harford County, 0.71 mi NE of Abingdon to 0.61 mi NE of Abingdon
Cause: Heavy Rain / Tropical System
Reported by: Emergency Manager
Coordinates: 39.477, -76.260

A small creek near James Run was over its banks around Route 7.

Flood, Montgomery

When: September 6, 5:10 PM EST to 6:15 PM EST
Where: Montgomery County, 0.23 mi ENE of Parkside to 0.73 mi ENE of Homewood
Cause: Heavy Rain / Tropical System
Reported by: Amateur Radio
Coordinates: 39.031, -77.076

Kensington road at Beach road remained closed due to flooding. Beach Drive and Sligo Creek Parkway also remained shut down due to high water.

What these are

Tropical Storm: A tropical cyclone with sustained winds of 34 to 63 knots (39 to 73 mph).
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 2008 Every state in 2008 This day in weather history Warnings in Maryland, September 2008 The 2008 hurricane season

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 2026-10-01. Each event’s entry at NCEI: 135906, 135886, 135912, 136101, 135917, 136102, 135850, 135918, 135883, 135890.