Flash Flooding and Flooding in Pennsylvania, August 19, 2011

Name: Flash Flooding and Flooding in Pennsylvania, August 19, 2011
Start: 2011-08-19T06:36
End: 2011-08-19T19:00
Location: Pennsylvania

August 19, 2011 · NWS PBZ · 53 events in 9 counties and zones

A slow moving cold front and a moist unstable airmass combined to produce scattered severe thunderstorms and flash flooding across eastern Ohio and Western Pennsylvania. 5 inches of rain fell in a very urbanized area just east of downtown Pittsburgh on Washington Blvd in just under an hour.

Where it happened

Every event with a place to put it. 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: 4
Injuries: 1
Property damage: $1.7 million
Crop damage: None recorded
Events: 53

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 PBZ wrote it up.

A slow moving cold front and a moist unstable airmass combined to produce scattered severe thunderstorms and flash flooding across eastern Ohio and Western Pennsylvania. Flash flooding was deadly in Pittsburgh when approximately 2.5 inches of rain fell in a very urbanized area just east of downtown Pittsburgh on Washington Blvd in just under an hour. This resulted in four fatalities and up to 15 water rescues.

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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Aug 19, 5:16 AM EST, 1 hour 20 minutes earlier.

Area forecast discussion, Aug 19, 5:16 AM EST, 1 hour 20 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
616 AM EDT FRI AUG 19 2011

.SYNOPSIS...
A WEAK COLD FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS
TODAY INTO THIS EVENING. HIGH PRESSURE WILL BRING DRY WEATHER FOR
SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPDATED FORECAST TO INCREASE POPS IN PORTIONS OF OHIO WHERE SCT
DEVELOPMENT IS OCCURRING.

A WEAK COLD FRONT WILL MOVE SLOWLY ACROSS THE DISTRICT THIS MORNING
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS INTO THIS EVENING.
HIGH PRESSURE BUILDING INTO THE DISTRICT TONIGHT WILL BRING AN END
TO THE SHOWERS BY EARLY SATURDAY MORNING.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BRING DRY WEATHER FOR SATURDAY INTO SATURDAY
EVENING. A COLD FRONT IS THEN EXPECTED TO COME THROUGH SATURDAY
NIGHT INTO SUNDAY. WILL CONTINUE CHANCE POPS FOR THIS
PERIOD...ALTHOUGH LOW CONFIDENCE AS TO ANY PARTICULAR LOCATION
WITH A HIGHER CHANCE OF RAIN. EXPECT SLIGHTLY WARMER TEMPERATURES
ON SATURDAY THAN SUNDAY WITH LESS CLOUD COVER.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
INSTABILITY ASSOCIATED WITH UPPER TROUGH MOVING SLOWLY ACROSS
EASTERN CANADA WILL MAINTAIN SCATTERED SHOWERS AND PERHAPS SOME
ISOLATED STORMS SUNDAY NIGHT AND MONDAY. SURFACE HIGH PRESSURE WILL
DRIFT EAST ALONG THE OHIO VALLEY TUESDAY AND OFF THE MID ATLANTIC
COAST BY THURSDAY. DRY WEATHER IS FORECAST FOR THE MIDDLE OF THE
WEEK...WITH NEAR NORMAL TEMPERATURES WARMING TO AROUND 5 DEGREES
ABOVE NORMAL BY THURSDAY.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
AREA OF SHOWERS/STORMS IS AVOIDING PORTS. ACTIVITY IS POPPING UP,
BUT NOTHING IS EXPECTED IN THE VICINITY OF THE PORTS UNTIL LATER
IN THE DAY.

WILL GO WITH A GENERAL VFR FORECAST TODAY. HIGH AND MID CLOUDS
ARE EXPECTED THROUGH MOST OF THE MORNING, WITH MVFR FOG BURNING
OFF BY 13Z.

WITH WEAK COOL FRONT SAGGING THROUGH THE UPPER OHIO VALLEY TODAY,
EXPECT SCT-BKN CU TO DEVELOP DURING THE MORNING HOURS. MODELS ARE
SHOWING ACTIVITY DEVELOPING WITH DAYTIME HEATING, BUT MAINLY OVER
THE EASTERN HALF OF THE AREA. WITH LOW CONFIDENCE, WILL INCLUDE A
TEMPO GROUP FOR THUNDER IN MOST EASTERN PORTS WITH FRONTAL PASSAGE.

CU WILL DISSIPATE AS THE SUNSETS.

OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
EXPECT MAINLY VFR FRIDAY NIGHT AND SATURDAY. THUNDERSTORMS WITH
RESTRICTIONS MAY BE POSSIBLE SATURDAY NIGHT INTO MONDAY WITH THE
SLOW EASTWARD PASSAGE OF A COLD FRONT. VFR SHOULD ENSUE BY TUESDAY.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

Hazardous weather outlook, Aug 19, 4:10 AM EST, 2 hours 26 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PITTSBURGH PA
510 AM EDT FRI AUG 19 2011

MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-
029-031-073>076-WVZ001>004-012-021>023-041-200915-
GARRETT-TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-
JEFFERSON OH-MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-VENANGO-
FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY-
ARMSTRONG-INDIANA-WASHINGTON-GREENE-WESTMORELAND-WESTMORELAND RIDGES-
FAYETTE-FAYETTE RIDGES-HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-MARION-
MONONGALIA-PRESTON-TUCKER-
510 AM EDT FRI AUG 19 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST
CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST
PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA
AND NORTHERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Special weather statement, Aug 19, 5:54 AM EST, 42 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
654 AM EDT FRI AUG 19 2011

OHZ041-PAZ020-191200-
BEAVER PA-COLUMBIANA OH-
654 AM EDT FRI AUG 19 2011

...THUNDERSTORMS PRODUCING HAIL...

HAIL PRODUCING THUNDERSTORMS MOVING THROUGH COLUMBIANA COUNTY TOWARD
BEAVER COUNTY...

AT 648 AM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH
INDICATED STRONG THUNDERSTORMS 4 MILES SOUTHWEST OF LISBON...MOVING
EAST AT 20 MPH. THESE STORMS WILL PRODUCE HAIL AND BRIEF HEAVY
DOWNPOURS.

SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE...
  MILLPORT...           GUILFORD LAKE STATE PARK...
  LISBON...             BEAVER CREEK STATE PARK...
  EAST PALESTINE...

KEEP AN EYE TO THE SKY AND MOVE TO A SAFE PLACE IF THUNDERSTORMS
APPROACH.

PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.

LAT...LON 4085 8046 4065 8046 4066 8090 4084 8091

The radar

The Pittsburgh radar (KPBZ), 50 km away, was scanning. The volume nearest the first event began at 11:36 UTC.

Open the radar archive at this moment

Event by event

25 hail, 15 thunderstorm wind, 9 flood, 4 flash flood. Local standard time, as filed.

Hail, Lawrence

When: August 19, 6:36 AM EST
Where: Lawrence County, 1.48 mi SSE of Mt Jackson
Measured: 0.88 in hail
Reported by: Public
Coordinates: 40.950, -80.420

Hail, Lawrence

When: August 19, 6:42 AM EST
Where: Lawrence County, New Castle
Measured: 0.88 in hail
Reported by: Public
Coordinates: 41.000, -80.350

Hail, Clarion

When: August 19, 8:41 AM EST
Where: Clarion County, 1.73 mi NE of Miola
Measured: 0.88 in hail
Reported by: Public
Coordinates: 41.270, -79.330

Hail, Clarion

When: August 19, 8:44 AM EST
Where: Clarion County, 0.86 mi SW of Clarion Parker Arpt
Measured: 0.88 in hail
Reported by: Public
Coordinates: 41.210, -79.380

Hail, Jefferson

When: August 19, 9:16 AM EST
Where: Jefferson County, 1.25 mi WNW of Roseville
Measured: 0.75 in hail
Reported by: Public
Coordinates: 41.190, -79.170

Hail, Jefferson

When: August 19, 9:34 AM EST
Where: Jefferson County, Corsica
Measured: 0.75 in hail
Reported by: Public
Coordinates: 41.180, -79.200

Thunderstorm Wind, Allegheny

When: August 19, 9:45 AM EST
Where: Allegheny County, 0.53 mi W of Elizabeth
Measured: 50 kt (58 mph) estimated gust
Property damage: $10,000
Reported by: Public
Coordinates: 40.270, -79.890

The public reported large branches broken off trees.

Hail, Mercer

When: August 19, 12:12 PM EST
Where: Mercer County, Mercer
Measured: 1 in hail
Reported by: Public
Coordinates: 41.230, -80.230

Hail, Mercer

When: August 19, 12:16 PM EST
Where: Mercer County, 1.25 mi WSW of Mercer
Measured: 1 in hail
Reported by: Public
Coordinates: 41.220, -80.250

Hail, Mercer

When: August 19, 12:27 PM EST
Where: Mercer County, Grove City
Measured: 1.25 in hail
Reported by: Public
Coordinates: 41.170, -80.080

Hail, Mercer

When: August 19, 12:32 PM EST
Where: Mercer County, 0.52 mi E of Henlein
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 41.400, -80.370

Hail, Mercer

When: August 19, 12:34 PM EST
Where: Mercer County, 0.86 mi SW of Grove City
Measured: 0.88 in hail
Reported by: Law Enforcement
Coordinates: 41.160, -80.090

Hail, Mercer

When: August 19, 12:38 PM EST
Where: Mercer County, Grove City
Measured: 1 in hail
Reported by: Public
Coordinates: 41.170, -80.080

Hail, Venango

When: August 19, 12:48 PM EST
Where: Venango County, 0.69 mi N of Barkeyville
Measured: 1.5 in hail
Reported by: Fire Department/Rescue
Coordinates: 41.190, -79.980

Hail, Mercer

When: August 19, 12:49 PM EST
Where: Mercer County, 0.86 mi SW of Grove City
Measured: 1.25 in hail
Reported by: Public
Coordinates: 41.160, -80.090

Hail, Mercer

When: August 19, 12:54 PM EST
Where: Mercer County, Grove City
Measured: 1 in hail
Reported by: Public
Coordinates: 41.170, -80.080

Hail, Mercer

When: August 19, 12:58 PM EST
Where: Mercer County, Grove City
Measured: 1 in hail
Reported by: Public
Coordinates: 41.170, -80.080

Hail, Mercer

When: August 19, 1:57 PM EST
Where: Mercer County, 0.69 mi S of West Middlesex
Measured: 0.75 in hail
Reported by: Public
Coordinates: 41.170, -80.450

Hail, Mercer

When: August 19, 2:10 PM EST
Where: Mercer County, 3.32 mi SW of Mercer
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 41.200, -80.280

Hail, Beaver

When: August 19, 2:25 PM EST
Where: Beaver County, 0.69 mi N of Colona
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 40.690, -80.270

Hail, Beaver

When: August 19, 2:26 PM EST
Where: Beaver County, 1.26 mi WNW of Wall Rose
Measured: 0.88 in hail
Reported by: Public
Coordinates: 40.640, -80.170

Thunderstorm Wind, Beaver

When: August 19, 2:30 PM EST
Where: Beaver County, 0.87 mi NE of Economy
Measured: 50 kt (58 mph) estimated gust
Property damage: $35,000
Reported by: Law Enforcement
Coordinates: 40.640, -80.190

Law enforcement reported power lines down.

Hail, Lawrence

When: August 19, 2:31 PM EST
Where: Lawrence County, 1.04 mi E of New Bedford
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 41.100, -80.500

Flood, Beaver

When: August 19, 2:38 PM EST to 7:00 PM EST
Where: Beaver County, 0.87 mi SW of Conway to 0.79 mi SW of Conway
Cause: Heavy Rain
Property damage: $50,000
Reported by: Emergency Manager
Coordinates: 40.660, -80.240

Emergency management reported 13th ST was flooded with standing water.

Flood, Mercer

When: August 19, 2:45 PM EST to 5:00 PM EST
Where: Mercer County, 4.65 mi WSW of Milburn to 2.38 mi SE of Greenfield
Cause: Heavy Rain
Property damage: $50,000
Reported by: Trained Spotter
Coordinates: 41.140, -80.310

A trained spotter reported standing water flooding SR 158 between New Wilmington and Mercer.

Hail, Beaver

When: August 19, 2:50 PM EST
Where: Beaver County, 1.05 mi E of Ambridge
Measured: 0.75 in hail
Reported by: Public
Coordinates: 40.600, -80.210

Hail, Beaver

When: August 19, 2:53 PM EST
Where: Beaver County, 1.26 mi WSW of Aliquippa Arpt
Measured: 0.75 in hail
Reported by: Public
Coordinates: 40.590, -80.320

Thunderstorm Wind, Allegheny

When: August 19, 3:01 PM EST
Where: Allegheny County, 0.87 mi SW of Leetsdale
Measured: 50 kt (58 mph) estimated gust
Property damage: $35,000
Reported by: Emergency Manager
Coordinates: 40.560, -80.210

Emergency management reported trees down.

Flood, Beaver

When: August 19, 3:05 PM EST to 7:00 PM EST
Where: Beaver County, 0.49 mi SSE of West Aliquippa to 0.57 mi S of West Aliquippa
Cause: Heavy Rain
Property damage: $75,000
Reported by: Law Enforcement
Coordinates: 40.623, -80.228

Law enforcement reported flooding with standing water on State Street and Duss Ave.

Flood, Beaver

When: August 19, 3:05 PM EST to 7:00 PM EST
Where: Beaver County, 1.34 mi NE of Shafers to 1.45 mi NE of Shafers
Cause: Heavy Rain
Property damage: $20,000
Reported by: Law Enforcement
Coordinates: 40.663, -80.301

Law enforcement reported standing water and flooding on Sassafra Lane.

Flood, Beaver

When: August 19, 3:09 PM EST to 7:00 PM EST
Where: Beaver County, 0.69 mi S of Ambridge to 0.44 mi NNW of South Hgts
Cause: Heavy Rain
Property damage: $25,000
Reported by: Emergency Manager
Coordinates: 40.590, -80.230

Emergency management reported standing water and flooding of Ohio River BLVD.

Hail, Allegheny

When: August 19, 3:11 PM EST
Where: Allegheny County, 2.95 mi SE of Cherry City
Measured: 0.88 in hail
Reported by: Public
Coordinates: 40.450, -79.930

Flood, Beaver

When: August 19, 3:15 PM EST to 7:00 PM EST
Where: Beaver County, 0.92 mi N of West Aliquippa to 0.86 mi N of West Aliquippa
Cause: Heavy Rain
Property damage: $25,000
Reported by: Emergency Manager
Coordinates: 40.643, -80.230

Emergency management reported standing water and flooding on Tevebaugh Rd in Baden.

Thunderstorm Wind, Westmoreland

When: August 19, 3:22 PM EST
Where: Westmoreland County, New Kensington
Measured: 50 kt (58 mph) estimated gust
Property damage: $50,000
Reported by: Emergency Manager
Coordinates: 40.570, -79.770

Emergency management reported power lines down.

Flash Flood, Allegheny

When: August 19, 3:36 PM EST to 6:00 PM EST
Where: Allegheny County, 1.24 mi SSW of Sharpsburg to 1.54 mi SSW of Sharpsburg
Cause: Heavy Rain
Deaths: 4 direct, 0 indirect
Injuries: 1 direct, 0 indirect
Property damage: $500,000
Reported by: NWS Storm Survey
Coordinates: 40.483, -79.909

A NWS storm survey found that 2.5 inches of rain fell in one hour in a very urbanized 4.8 sq mi watershed just east of downtown Pittsburgh. Severe flash flooding developed on Washington Blvd resulting in four fatalities and up to 15 water rescues. A mother and two daughters were drowned inside a van when it became submerged in approximately 9 10 feet of water. An elderly lady who abandoned her car was apparently swept or fell into an open manhole or catch basin and drowned.

Flood, Beaver

When: August 19, 3:39 PM EST to 7:00 PM EST
Where: Beaver County, 0.7 mi SW of Beaver Falls to 0.54 mi SW of Beaver Falls
Cause: Heavy Rain
Property damage: $75,000
Reported by: Emergency Manager
Coordinates: 40.744, -80.341

Emergency management reported flooding and a mudslide on Constitution BLVD.

Thunderstorm Wind, Washington

When: August 19, 3:40 PM EST
Where: Washington County, 1.26 mi ENE of Bower Hill
Measured: 50 kt (58 mph) estimated gust
Reported by: Law Enforcement
Coordinates: 40.280, -80.050

Law enforcement reported trees down.

Thunderstorm Wind, Washington

When: August 19, 3:40 PM EST
Where: Washington County, 0.53 mi E of Venetia
Measured: 50 kt (58 mph) estimated gust
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 40.250, -80.040

Law enforcement reported a large tree down on Bebout Rd.

Flash Flood, Allegheny

When: August 19, 3:45 PM EST to 6:00 PM EST
Where: Allegheny County, 1.43 mi N of Option to 1.57 mi N of Option
Cause: Heavy Rain
Property damage: $50,000
Reported by: Emergency Manager
Coordinates: 40.451, -79.980

Emergency management reported flash flooding on Bigelow BLVD at Frank Curto Park closing the road.

Thunderstorm Wind, Washington

When: August 19, 3:48 PM EST
Where: Washington County, 1.05 mi E of Finleyville
Measured: 50 kt (58 mph) estimated gust
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 40.250, -80.000

Law enforcement reported a large tree down on Elrama Rd.

Thunderstorm Wind, Washington

When: August 19, 3:48 PM EST
Where: Washington County, 0.53 mi E of Monongahela
Measured: 50 kt (58 mph) estimated gust
Property damage: $50,000
Reported by: Law Enforcement
Coordinates: 40.200, -79.920

Law enforcement reported large trees down on Hillman Steet and James Street.

Thunderstorm Wind, Washington

When: August 19, 3:50 PM EST
Where: Washington County, 1.05 mi E of Finleyville
Measured: 50 kt (58 mph) estimated gust
Property damage: $25,000
Reported by: Law Enforcement
Coordinates: 40.250, -80.000

Law enforcement reported a telephone pole down on Coal Bluff Road.

Flood, Washington

When: August 19, 3:55 PM EST to 7:00 PM EST
Where: Washington County, 1.07 mi SSE of Gastonville to 0.86 mi WNW of Coal Bluff
Cause: Heavy Rain
Property damage: $40,000
Reported by: Law Enforcement
Coordinates: 40.256, -79.990

Law enforcement reported Elrama RD flooded.

Thunderstorm Wind, Washington

When: August 19, 3:57 PM EST
Where: Washington County, 0.87 mi SE of Donora
Measured: 50 kt (58 mph) estimated gust
Property damage: $35,000
Reported by: Law Enforcement
Coordinates: 40.170, -79.860

Law enforcement reported power lines down on Watkins Avenue.

Thunderstorm Wind, Allegheny

When: August 19, 3:59 PM EST
Where: Allegheny County, 0.53 mi W of Elizabeth
Measured: 50 kt (58 mph) estimated gust
Property damage: $25,000
Reported by: Public
Coordinates: 40.270, -79.890

The public reported large branches down.

Thunderstorm Wind, Westmoreland

When: August 19, 4:00 PM EST
Where: Westmoreland County, 1.38 mi N of Fellsburg
Measured: 50 kt (58 mph) estimated gust
Property damage: $35,000
Reported by: Law Enforcement
Coordinates: 40.200, -79.820

Law enforcement reported trees down.

Thunderstorm Wind, Washington

When: August 19, 4:04 PM EST
Where: Washington County, 0.53 mi E of Monongahela
Measured: 50 kt (58 mph) estimated gust
Property damage: $25,000
Reported by: Public
Coordinates: 40.200, -79.920

The public reported large branches down.

Hail, Washington

When: August 19, 4:05 PM EST
Where: Washington County, 0.87 mi SE of Donora
Measured: 0.75 in hail
Reported by: Trained Spotter
Coordinates: 40.170, -79.860

Thunderstorm Wind, Westmoreland

When: August 19, 4:10 PM EST
Where: Westmoreland County, Wyano
Measured: 50 kt (58 mph) estimated gust
Property damage: $35,000
Reported by: Law Enforcement
Coordinates: 40.200, -79.700

Law enforcement reported trees down.

Flood, Beaver

When: August 19, 4:17 PM EST to 7:00 PM EST
Where: Beaver County, 0.97 mi NNW of Davidson Hgts to 1.13 mi NNW of Davidson Hgts
Cause: Heavy Rain
Property damage: $75,000
Reported by: Newspaper
Coordinates: 40.612, -80.260

A newspaper reported flooding with mud and debris into businesses on Franklin Ave.

Thunderstorm Wind, Westmoreland

When: August 19, 4:34 PM EST
Where: Westmoreland County, 0.53 mi W of Monessen
Measured: 50 kt (58 mph) estimated gust
Property damage: $100,000
Reported by: Public
Coordinates: 40.150, -79.890

The public reported shingles blown off and large tree branches down on homes.

Flash Flood, Beaver

When: August 19, 4:36 PM EST to 7:00 PM EST
Where: Beaver County, 0.72 mi N of Davidson Hgts to 0.4 mi N of Davidson Hgts
Cause: Heavy Rain
Property damage: $100,000
Reported by: Emergency Manager
Coordinates: 40.610, -80.250

Emergency management reported flash flooding with 2 to 3 feet of water flowing across Sohn Road with debris.

Flash Flood, Beaver

When: August 19, 5:43 PM EST to 7:00 PM EST
Where: Beaver County, 0.87 mi SW of Bridgewater to 0.35 mi SW of Bridgewater
Cause: Heavy Rain
Property damage: $100,000
Reported by: Emergency Manager
Coordinates: 40.690, -80.310

Emergency management reported flash flooding in Beaver with debris flow in streets and water in a few buildings.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Flash Flood, Allegheny	2011-08-19	45	Female	Vehicle/Towed Trailer	Direct
Flash Flood, Allegheny	2011-08-19	12	Female	Vehicle/Towed Trailer	Direct
Flash Flood, Allegheny	2011-08-19	8	Female	Vehicle/Towed Trailer	Direct
Flash Flood, Allegheny	2011-08-19	72	Female	Vehicle/Towed Trailer	Direct

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
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.

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

The same day elsewhere

Every storm in Pennsylvania in 2011 Every state in 2011 This day in weather history Warnings in Pennsylvania, August 2011

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: 334840, 334829, 334841, 334830, 334842, 334832, 334862, 334844, 334833, 334845, 334834, 334835, 334846, 334837, 334838, 334852, 334853, 334854, 334858, 334847, 334855, 334864, 334848, 334816, 334817, 334856, 334857, 334865, 334818, 334819, 334820, 334877, 334823, 334869, 334799, 334825, 334878, 334879, 334800, 334880, and more.