Outflow boundaries from convection earlier in the day helped to spark additional thunderstorms in the afternoon and evening on the 9th ahead of an approaching cold front. Where the boundaries collided, thunderstorms with very heavy rain materialized, with rates approaching 2 inches per hour based on radar estimates and spotter reports. Convection started over Etna and Shaler, in northern Allegheny county and propogated northward toward Monaca, Ambridge, and Aliquippa in Beaver county. Several road closures were reported with several feet of water on roadways in both locations.

Thunderstorm Wind in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 15:58:00 to 09-SEP-15 15:58:00 (EST-5)
Location: ELFINWILD
Magnitude: 50.00 EG
Property damage: 1.50K
Crop damage: 0.00K
Reported by: 911 Call Center

Local 911 call center reported trees down in Shaler and O'Hara Township.

Heavy Rain in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:00:00 to 09-SEP-15 19:10:00 (EST-5)
Location: ALIQUIPPA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

National Weather Service employee reported 5.22 inches of rain occurred in a little over two hours.

Flash Flood in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:55:00 to 09-SEP-15 20:30:00 (EST-5)
Location: FREEDOM ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Local 911 center reported that Route 989 was closed due to flash flooding near Economy.

Flash Flood in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:55:00 to 09-SEP-15 20:30:00 (EST-5)
Location: DAVIDSON HGTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Local 911 reported that Franklin Avenue is closed due to flash flooding in Aliquippa.

Flash Flood in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:55:00 to 09-SEP-15 20:30:00 (EST-5)
Location: WEST ALIQUIPPA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Local 911 reported that both Forest Street in Baden and Route 65 in Ambridge are closed due to flooding. One person was pulled from a vehicle trapped in high water on Route 65.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 16:30:00 to 09-SEP-15 19:00:00 (EST-5)
Location: ETNA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Local 911 reported Butler Street, near the Advance Auto Parts, was closed due to flooding. In addition, the intersection with Crescent Road was shut down.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 16:30:00 to 09-SEP-15 19:00:00 (EST-5)
Location: SHALECREST
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Local 911 center reported several roadways closed in and around Shaler due to flash flooding. The roadways included Saxonburg Boulevard, with debris reported on the roadway; Route 8 between McDonalds and Kmart; and the intersection of Glen Scott and Glenn Douglas Drive, where one foot of water was reported on the roadway. Also, a landslide was reported on Middle Road and sewage was backing up into flooded homes on Morgan Avenue.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 16:30:00 to 09-SEP-15 19:00:00 (EST-5)
Location: SHALECREST
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Local 911 reported that the northbound lane of William Flynn Highway, at the intersection of Spencer Lane was flooded and being shut down. Six cars were reported to be stuck in water, which was half way up the doors. Also, there was water flowing into the Goss Gas building. In addition, the intersection of Maple and Glenn Avenues was reported to be flooded with a partial roadway collapse.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 16:53:00 to 09-SEP-15 18:00:00 (EST-5)
Location: BLAWNOX
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Local 911 center reported that the intersection of Delta and Alpha Drive was flooded, with water up to the windows of cars.

Flash Flood in ALLEGHENY, PENNSYLVANIA
From 09-SEP-15 17:55:00 to 09-SEP-15 20:30:00 (EST-5)
Location: BELL ACRES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Local 911 reported numerous roads closed around Bell Acres.

Heavy Rain in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:28:00 to 09-SEP-15 18:28:00 (EST-5)
Location: COLONA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 1.9 inches in one hour.

Heavy Rain in BEAVER, PENNSYLVANIA
From 09-SEP-15 17:08:00 to 09-SEP-15 18:08:00 (EST-5)
Location: CONWAY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

National Weather Service employee reported 2 inches in one hour.