A lee pressure trough and weak cold front combined to ignite numerous thunderstorms in a strongly unstable environment. The strongest thunderstorms produced severe wind gusts and sporadic hail.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 11-AUG-21 14:04:00 to 11-AUG-21 14:04:00 (EST-5)
Location: WILLIAMSPORT
Magnitude: 48.00 MG
Property damage: 1.00K
Reported by: Mesonet

A wind gust of 48 knots (55 MPH) was measured by a mesonet at Springfield Middle School in Williamsport. The wind caused minor tree damage nearby, including a tree that blew down on Falling Waters Road.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 11-AUG-21 14:10:00 to 11-AUG-21 14:10:00 (EST-5)
Location: HAGERSTOWN
Magnitude: 50.00 EG
Property damage: 6.00K
Reported by: 911 Call Center

There were several reports of trees blown down in Hagerstown.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 11-AUG-21 14:20:00 to 11-AUG-21 14:20:00 (EST-5)
Location: BOONSBORO
Magnitude: 60.00 EG
Property damage: 20.00K
Reported by: 911 Call Center

There were numerous reports of trees blown down in and around Boonsboro.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:25:00 to 11-AUG-21 14:25:00 (EST-5)
Location: CATOCTIN
Magnitude: 55.00 EG
Property damage: 10.00K
Reported by: Department of Highways

Trees blew down on MD-464 Point of Rocks Road between Lander Road and Fry Road. Several trees blew down along Pleasant View Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:40:00 to 11-AUG-21 14:40:00 (EST-5)
Location: MYERSVILLE
Magnitude: 60.00 EG
Property damage: 20.00K
Reported by: 911 Call Center

There were numerous reports of trees blown down in and around Myersville, including near the intersection of US-40 Baltimore National Pike and MD-17 Wolfsville Road. Wires blew down in the 2100 block of Monument Road. Several trees blew down along Harmony Road, Spruce Run Road and Hayes Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:40:00 to 11-AUG-21 14:40:00 (EST-5)
Location: ELLERTON
Magnitude: 60.00 EG
Property damage: 20.00K
Reported by: Fire Department/Rescue

Numerous trees blew down onto Easterday Road between Pleasant Walk Road and Ward Kline Road. Numerous trees blew down on Woodland Way Road between Church Hill Road and Easterday Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:45:00 to 11-AUG-21 14:45:00 (EST-5)
Location: WOLFSVILLE
Magnitude: 55.00 EG
Property damage: 12.00K
Reported by: Fire Department/Rescue

Numerous trees blew down onto Stottlemyer Road between Hayes Road and Brandenburg Hollow Road. Several trees blew down along Legore Road, Dahlgren Road and Highland School Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:50:00 to 11-AUG-21 14:50:00 (EST-5)
Location: FREDERICK
Magnitude: 50.00 EG
Property damage: 6.00K
Reported by: 911 Call Center

There were several reports of trees blown down in and near the city of Frederick, including along Opossumtown Pike.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 14:52:00 to 11-AUG-21 14:52:00 (EST-5)
Location: URBANA
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Department of Highways

Trees blew down onto southbound I-270 Washington National Pike/Dwight D. Eisenhower Memorial Highway between Exit 26/MD-80 Fingerboard Road and Exit 22/MD-109 Old Hundred Road. Trees blew down along Doctor Perry Road and Thurston Road.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 11-AUG-21 15:00:00 to 11-AUG-21 15:00:00 (EST-5)
Location: DAWSONVILLE
Magnitude: 40.00 EG
Property damage: 1.00K
Reported by: Department of Highways

A tree was reported down near the intersection of MD-107 Whites Ferry Road and Partnership Road.

Thunderstorm Wind in FREDERICK, MARYLAND
From 11-AUG-21 15:05:00 to 11-AUG-21 15:05:00 (EST-5)
Location: UNIONVILLE
Magnitude: 55.00 EG
Property damage: 10.00K
Reported by: Fire Department/Rescue

Several trees blew down along Bessie Clemson Road, Putman Road and Bethel Road.

Thunderstorm Wind in CARROLL, MARYLAND
From 11-AUG-21 15:30:00 to 11-AUG-21 15:30:00 (EST-5)
Location: WESTMINSTER
Magnitude: 50.00 EG
Property damage: 3.00K
Reported by: 911 Call Center

A few trees blew down in the Westminster area.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 11-AUG-21 15:33:00 to 11-AUG-21 15:33:00 (EST-5)
Location: POTOMAC
Magnitude: 50.00 EG
Property damage: 3.00K
Reported by: Emergency Manager

A tree blew down onto a vehicle in the 10000 block of MD-190 River Road.

Lightning in FREDERICK, MARYLAND
From 11-AUG-21 15:01:00 to 11-AUG-21 15:01:00 (EST-5)
Location: IJAMSVILLE
Property damage: 300.00K
Reported by: Emergency Manager

Lightning struck a house causing a fire in the 9500 block of Ball Road. The fire caused the structure to collapse, killing a firefighter who was inside.

Thunderstorm Wind in WASHINGTON, MARYLAND
From 11-AUG-21 15:36:00 to 11-AUG-21 15:36:00 (EST-5)
Location: MOFFET
Magnitude: 50.00 EG
Property damage: 2.00K
Reported by: NWS Employee

A tree and several large branches blew down near Orchard Ridge Road.

Thunderstorm Wind in CARROLL, MARYLAND
From 11-AUG-21 15:44:00 to 11-AUG-21 15:44:00 (EST-5)
Location: MANCHESTER
Magnitude: 50.00 EG
Property damage: 3.00K
Reported by: 911 Call Center

A few trees blew down in the Manchester area.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 11-AUG-21 15:44:00 to 11-AUG-21 15:44:00 (EST-5)
Location: NORBECK
Magnitude: 50.00 EG
Property damage: 4.00K
Reported by: Department of Highways

Trees blew down on MD-28 Norbeck Road at Carrolton Road, and on MD-97 Georgia Avenue at International Drive.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 11-AUG-21 15:50:00 to 11-AUG-21 15:50:00 (EST-5)
Location: PARKWOOD
Magnitude: 65.00 EG
Property damage: 500.00K
Reported by: Emergency Manager

Dozens of trees, large branches and wires blew down in the Bethesda, Kensington and Chevy Chase area. Wires blew down in the 5500 block of Johnson Avenue. Trees blew down onto wires on MD-187 Old Georgetown Road at Bell Mills Road. Trees blew down on I-495 Capital Beltway near Exit 33/MD-185 Connecticut Avenue, and between Exit 34/MD-355 Rockville Pike and Exit 35/I-270 Washington National Pike blocking the entire Inner Loop. Trees blew down on southbound MD-355 Rockville Pike at I-495 Capital Beltway and south of Tuckerman Lane. A large tree fell and took down wires near the intersection of Whittier Boulevard and Orchid Drive. Several large trees and branches took down wires and several transformers in the 5700 block of Grosvenor Lane, damaging several utility poles. A few large trees blew down near the intersection of Beech Avenue and MD-187 Old Georgetown Road. A tree blew down onto a house on Lundigan Court. A tree fell onto a vehicle and wires on Alta Vista Road, and a pedestrian was injured when they were struck by flying debris. Some homes suffered damage from falling trees on Chatsworth Drive, Farnham Road, and Rossmore Road. Multiple large trees blew down blocking Fernwood Road near I-495 Capital Beltway. Numerous trees were blown down near the Wildwood Shopping Center. A large tree fell onto wires and a house causing significant structural damage in the 10400 block of Muir Place; another large tree blew onto a house causing significant structural damage in the 5200 block of Acacia Avenue. Multiple trees and wires blew down in the 6000 block of Chatsworth Lane. A tree fell onto wires and a house on York Lane near Overhill Road. A tree blew down on Tuckerman Lane near Whisperwood Lane. A tree blew down onto a house in the 10100 block of Wildwood Road. Trees and wires blew down in the 10000 block of Weymouth Street. A tree blew down onto an unoccupied vehicle on I-495 Capital Beltway Inner Loop between Exit 33/MD-185 Connecticut Avenue and Exit 35/I-270 Washington National Pike. Wires blew down in the 10100 block of Ashburton Lane.

Thunderstorm Wind in MONTGOMERY, MARYLAND
From 11-AUG-21 15:55:00 to 11-AUG-21 15:55:00 (EST-5)
Location: CAPITOL VIEW PARK
Magnitude: 50.00 EG
Property damage: 5.00K
Reported by: Emergency Manager

Several trees, large branches and wires blew down near Silver Spring and Takoma Park. Trees blew down on eastbound I-495 Capital Beltway Inner Loop at Exit 30B/US-29 Colesville Road. Large tree limbs blew down on Forest Glen Road near Holy Cross Hospital. A tree blew down on westbound MD-410 East-West Highway just past US-29 Georgia Avenue. Wires blew down in the 1600 block of Oaklawn Court.

Thunderstorm Wind in BALTIMORE, MARYLAND
From 11-AUG-21 16:00:00 to 11-AUG-21 16:00:00 (EST-5)
Location: BUTLER
Magnitude: 40.00 EG
Property damage: 1.00K
Reported by: Emergency Manager

A tree was reported down on Cuba Road near Western Run Road.

Thunderstorm Wind in BALTIMORE, MARYLAND
From 11-AUG-21 16:05:00 to 11-AUG-21 16:05:00 (EST-5)
Location: MARYLAND LINE
Magnitude: 50.00 EG
Property damage: 4.00K
Reported by: Emergency Manager

Three trees blew down near the intersection of Harris Mill Road and Dunk Freeland Road. A tree blew down near the intersection of Ensor Road and Stablersville Road.

Thunderstorm Wind in HARFORD, MARYLAND
From 11-AUG-21 16:30:00 to 11-AUG-21 16:30:00 (EST-5)
Location: ROCKS
Magnitude: 45.00 EG
Property damage: 2.00K
Reported by: 911 Call Center

A tree was reported down on a power line causing a fire in the 3000 block of Rocks Chrome Hill Road.

Thunderstorm Wind in BALTIMORE, MARYLAND
From 11-AUG-21 16:40:00 to 11-AUG-21 16:40:00 (EST-5)
Location: ST HELENA
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: Emergency Manager

Wires blew down in the 7000 block of Bridgewood Drive.

Thunderstorm Wind in BALTIMORE, MARYLAND
From 11-AUG-21 16:43:00 to 11-AUG-21 16:43:00 (EST-5)
Location: UPPER FALLS
Magnitude: 50.00 EG
Property damage: 4.00K
Reported by: Emergency Manager

A tree blew down onto power lines in the 11000 block of Raphel Road. A large tree limb blew down onto wires causing a fire in the 10000 block of Gunridge Circle.

Thunderstorm Wind in BALTIMORE, MARYLAND
From 11-AUG-21 16:50:00 to 11-AUG-21 16:50:00 (EST-5)
Location: BALTIMORE MARTIN ST
Magnitude: 50.00 EG
Property damage: 2.00K
Reported by: Emergency Manager

A tree blew down onto power lines in the 11000 block of MD-150 Eastern Avenue.

Thunderstorm Wind in HARFORD, MARYLAND
From 11-AUG-21 17:14:00 to 11-AUG-21 17:14:00 (EST-5)
Location: SEWELL
Magnitude: 50.00 EG
Property damage: 1.00K
Reported by: 911 Call Center

Tree damage was reported near Harford, including a tree that blew down near the intersection of Church Creek Road and MD-543 Riverside Parkway.