Flash Flooding and Flooding in New Jersey, August 14 to 19, 2011

Name: Flash Flooding and Flooding in New Jersey, August 14 to 19, 2011
Start: 2011-08-14T00:00
End: 2011-08-19T00:45
Location: New Jersey

August 14 to 19, 2011 · NWS PHI · 20 events in 11 counties and zones

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: 1
Injuries: 0
Property damage: $25 million
Crop damage: None recorded
Events: 20

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 PHI wrote it up.

A series of thunderstorms preceding a cold front dropped three to seven inches of rain across a wide swath of New Jersey (less along most of the coast) from overnight on the 13th into the day on the 14th. But in southern Gloucester, Eastern Salem and Western Cumberland County, rainfall amounts reached seven to eleven inches. Scattered thunderstorms occurred into the 15th and morning of the 16th. This slowed the recession of rivers and streams in the state. The combined event caused severe flash flooding with dam breaks in southwestern New Jersey and flash flooding and flooding across central and northern New Jersey. Damage estimates reached around 25 million dollars, most of which occurred in Salem and Cumberland Counties.

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 Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Aug 13, 10:10 PM EST, 1 hour 50 minutes earlier.

Area forecast discussion, Aug 13, 10:10 PM EST, 1 hour 50 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1110 PM EDT SAT AUG 13 2011

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT FARTHER OFF THE COAST
OVERNIGHT AND SUNDAY. LOW PRESSURE, LOCATED OVER MICHIGAN THIS
AFTERNOON, WILL PROGRESS TO THE SOUTHEAST. THE LOW IS FORECAST TO
PASS OFF THE NEW JERSEY COAST EARLY ON MONDAY BEFORE MOVING SLOWLY
OUT TO SEA ON MONDAY AND TUESDAY. HIGH PRESSURE IS EXPECTED TO
FOLLOW FOR THE MID WEEK PERIOD. A WARM FRONT IS ANTICIPATED TO
APPROACH FROM THE SOUTH ON FRIDAY AND IT MAY ARRIVE IN OUR REGION
ON SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHOWERS AND EMBEDDED THUNDERSTORMS WILL CONTINUE ACROSS NORTHEAST
PENNSYLVANIA AND NORTHERN NEW JERSEY OVER THE NEXT SEVERAL HOURS.
THIS CONVECTION IS ASSOCIATED WITH AN ENHANCED AREA OF LIFT IN
THE LOW TO MID LEVELS. THIS AREA WILL SLOWLY MOVE NORTHEAST
OVERNIGHT, BUT SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
TO DEVELOP ACROSS THE AREA OVERNIGHT AS THE AIRMASS REMAINS VERY
MOIST AND UNSETTLED. ACTUALLY THEY HAVE ALREADY STARTED TO DEVELOP
ACROSS PORTIONS OF EASTERN MARYLAND AND WILL LIKELY CONTINUE AND
SLOWLY SPREAD NORTHEAST. SEVERAL FLASH FLOOD WARNINGS HAVE
ALREADY BEEN ISSUED FOR NORTHEAST PENNSYLVANIA AND NORTHERN NEW
JERSEY AS 1 TO 2 INCHES WITH HIGHER AMOUNTS OVER 3 INCHES HAVE
FALLEN ACROSS THESE AREAS, AND MORE HEAVY RAIN IS EXPECTED.

LOW TEMPERATURES FOR THE OVERNIGHT PERIOD WERE SHAVED DOWN A
DEGREE OR TWO BASED ON CURRENT TRENDS. BASICALLY LOWS AROUND 60
ARE EXPECTED IN THE HIGHER TERRAIN OF THE SOUTHERN POCONOS, AND
AROUND 70 OR SO IN THE PHILLY METRO AREA AND POINTS FURTHER SOUTH.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
AT MID AFTERNOON, THE MAIN MID LEVEL CIRCULATION WAS LOCATED OVER
NORTHERN MICHIGAN. ANOTHER VORTEX WAS ROTATING AROUND IT. THE
VORTEX WAS PASSING FROM EASTERN IOWA TO NORTHWESTERN ILLINOIS. THE
FEATURES WILL HEAD EASTWARD AND EVENTUALLY MELD TOGETHER. THE
RESULTING MID LEVEL CIRCULATION IS FORECAST TO PASS OVER OUR
REGION AROUND MONDAY NIGHT. UNTIL THAT TIME WE WILL EXPERIENCE A
PERIOD OF UNSETTLED WEATHER WITH SHOWERS AND THUNDERSTORMS.

WE HAVE ISSUED A FLOOD WATCH FOR OUR COUNTIES ALONG AND TO THE
NORTHWEST OF INTERSTATE 95. FOR NOW, IT IS IN EFFECT UNTIL 600 AM
MONDAY. HOWEVER, IT MAY NEED TO BE EXTENDED IN SPOTS.

WE ARE ANTICIPATING RAINFALL AMOUNTS IN THE 2 TO 3 INCH RANGE AT
MANY LOCATIONS WITH LOCALLY HIGHER AMOUNTS.

IT LOOKS AS THOUGH THE BEST MOISTURE FEED OFF THE OCEAN WILL BE
FROM SUNDAY AFTERNOON INTO SUNDAY NIGHT. IT COULD PRODUCE ENHANCED
RAINFALL AMOUNTS IN THE TERRAIN OF EASTERN PENNSYLVANIA AND
NORTHERN AND CENTRAL NEW JERSEY AT THAT TIME.

AFTER THE MID LEVEL LOW PASSES TO OUR EAST ON TUESDAY, CONDITIONS
SHOULD IMPROVE GRADUALLY.

WITH THE CLOUD COVER AND THE PRECIPITATION, TEMPERATURES SHOULD
VARY LITTLE. LOWS ARE FORECAST TO BE MAINLY FROM 65 TO 70 WITH
HIGHS NEAR 80.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THIS TIME FRAME HAS UNCERTAINTY WITH THE OVERALL SYNOPTIC FLOW
REGIME AS THE MODEL GUIDANCE HAS VARIATIONS OF THE TROUGH IN THE
NORTHWESTERN U.S. AND ACROSS WESTERN CANADA. THIS THEN HAS SOME
DOWNSTREAM AFFECTS WITH TIME. GIVEN LESS CERTAINTY WITH TIME, HPC
WENT WITH AN EVEN BLEND OF THE GFS AND ECMWF ENSEMBLE MEANS. THIS
IS BASICALLY TO RESOLVE THE DIFFERENCES BETWEEN THE OPERATIONAL
GUIDANCE. WE WENT WITH HPC GUIDANCE AS A RESULT WITH MAINLY JUST
SOME MINOR ADJUSTMENTS.

BASED ON THE ABOVE, AN UPPER-LEVEL TROUGH IS FORECAST TO BE
SLIDING TO OUR EAST TUESDAY NIGHT. FOR NOW, LEFT SOME SLIGHT CHC
POPS ACROSS THE EASTERN ZONES IN THE EVENING TO ACCOUNT FOR SOME
POSSIBLE SLOWER EXIT OF THIS SYSTEM. HIGH PRESSURE THEN GRADUALLY
BUILDS IN FOR WEDNESDAY AND THURSDAY AS A WEAK COLD FRONT CROSSES
MOSTLY NEW ENGLAND. THERE DOES NOT APPEAR TO BE MUCH MOISTURE OR
FORCING WITH THIS FEATURE. AS THE SURFACE HIGH SLIDES TO OUR EAST
LATER THURSDAY INTO FRIDAY, THE RETURN FLOW WILL ALLOW MOISTURE TO
INCREASE AND A COLD FRONT TO APPROACH FROM THE WEST. WE ALSO MAY
HAVE LEE SIDE TROUGH DEVELOPMENT DURING FRIDAY. THE FRONT MAY
EITHER STALL NEAR OUR AREA OR TEND TO REORGANIZE TO OUR SOUTHEAST
AS UPPER-LEVEL ENERGY MAY TRY TO SHARPEN SOME SATURDAY. THIS
CARRIES LOW CONFIDENCE, THEREFORE WILL GO WITH SLIGHT CHC TO LOWER
END CHC POPS THURSDAY THROUGH SATURDAY. AS FOR TEMPERATURES, WE
MOSTLY FOLLOWED HPC GUIDANCE BUT DID MAKE SOME TWEAKS ESPECIALLY
ALONG THE COAST.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

AREAS OF SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUE TO ROLL
NORTHEASTWARD ACROSS PORTIONS OF THE REGION. THE ACTIVITY ACROSS
SOUTHERN NEW JERSEY HAS WEAKENED SEVERAL TIMES AS IT HAS RUN INTO
A MORE STABLE ENVIRONMENT SO FAR. THERE CONTINUES TO BE LOCALLY HEAVY
DOWNPOURS WITH THE ACTIVITY, THEREFORE THE LOCAL VISIBILITY WILL
BRIEFLY LOWER TO 2SM OR LESS. MAINLY MVFR CEILINGS WILL ACCOMPANY
THE SHOWERS AND THUNDERSTORMS, WITH POSSIBLY BRIEF LOCAL WINDS
GUSTS TO NEAR 25 KNOTS EARLY THIS EVENING. OTHERWISE, A VFR DECK
WILL GENERALLY LOWER EVERYWHERE TONIGHT AS THE MOISTURE DEEPENS.

AN AREA OF LOW PRESSURE NEAR THE GREAT LAKES REGION WILL SLOWLY
MOVE EASTWARD THROUGH MONDAY. THIS ALONG WITH A DEEP SOUTHERLY
FLOW WILL ALLOW NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS TO
OCCUR TONIGHT THROUGH SUNDAY. SOME OF THE RAIN WILL BE LOCALLY
HEAVY, THEREFORE WHILE VISIBILITIES WILL VARY THEY WILL BE GREATLY
REDUCED DURING TIMES OF HEAVIER RAIN. WE MAINTAINED A LOWERING
CEILING TO MVFR TONIGHT AS THE MOISTURE DEEPENS AND NEARLY ALL
TERMINALS SEE AT LEAST SOME RAIN. WHILE SOME LOCAL IFR CONDITIONS
ARE POSSIBLE AT SOME POINT TONIGHT AND SUNDAY, OUR CONFIDENCE IS
LOW THEREFORE WE WILL NOT INCLUDE AT THIS TIME. THE SOUTH OR EVEN
SOUTHEAST FLOW FOR A TIME SUNDAY MAY ALLOW THE HEAVIER RAIN TO
BECOME FOCUSED INLAND FOR AWHILE, UNLESS A SURFACE LOW DEVELOPS
CLOSER TO THE COAST. AS OF NOW, WE ARE GENERALLY LEANING MORE
TOWARD A WEAKER SURFACE LOW THUS SPREADING OUT THE SHOWERS AND
LOCALLY HEAVY RAIN. THERE SHOULD BE SOME LULLS IN THE SHOWERS AND
SCATTERED THUNDERSTORMS, THEREFORE WE INDICATED SOME IMPROVEMENT
FOR A TIME SUNDAY HOWEVER CONFIDENCE IS LOW. WE USED A TEMPO GROUP
TO COVER THE LOCALLY HEAVIER ACTIVITY FOR AWHILE TONIGHT, THEN
ANOTHER ONE ON SUNDAY TO INDICATE OUR SOMEWHAT HIGHER CONFIDENCE
WHEN SOME HEAVIER ACTIVITY MAY OCCUR. WE WILL CONTINUE TO MONITOR
RADAR TRENDS AND ISSUE AMENDMENTS TO CONVEY THE LATEST THINKING.

A GENERAL SOUTHERLY WIND IS EXPECTED WITH SPEEDS 10 KNOTS OR LESS,
EXCEPT ANY LOCAL GUSTINESS ASSOCIATED WITH HEAVIER SHOWERS OR
THUNDERSTORMS. THE SOUTHERLY FLOW MAY INCREASE AND TURN A BIT
GUSTY SUNDAY FOR A TIME MAINLY AT KACY, KMIV AND KILG BASED ON THE
TRAJECTORY OFF THE WATER, HOWEVER SINCE CONFIDENCE IS LOW AT THIS
TIME NO GUSTS WERE INCLUDED.

OUTLOOK...
THE AFOREMENTIONED AREA OF LOW PRESSURE WILL CONTINUE TO SLOWLY
MOVE ACROSS THE REGION SUNDAY NIGHT AND MONDAY. IT WON'T BE
RAINING THE WHOLE TIME, BUT EXPECT SHOWERS TO CONTINUE SUNDAY
NIGHT FOLLOWED BY SOME IMPROVEMENT. EXPECT MAINLY MVFR DURING
THIS TIME ALTHOUGH THERE COULD BE LOCAL IFR IN DOWNPOURS. MONDAY
NIGHT INTO TUESDAY, MORE IMPROVEMENT IS FORECAST AS THE STORM
SYSTEM STARTS TO SHIFT TO OUR EAST. DRY WEATHER IS ANTICIPATED FOR
WEDNESDAY, THEN THE NEXT COLD FRONT APPROACHES THURSDAY WITH
PERHAPS A FEW SHOWERS OR THUNDERSTORMS.

&&

.MARINE...
HIGH PRESSURE TO OUR EAST TONIGHT AS AN AREA OF LOW PRESSURE BEGINS
TO SLOWLY MOVE EASTWARD THROUGH MONDAY. THIS LOW WILL BRING
SHOWERS AND SOME THUNDERSTORMS AND DETERIORATING CONDITIONS TO THE
AREA BEGINNING TONIGHT. THE WIND WILL INCREASE FROM THE SOUTH TO
SOUTHEAST AND WILL REACH AROUND 20 KT BY SUN AND SUN NIGHT. SEAS
SHOULD REACH AROUND 4 FT. THE LATEST WAVEWATCH DATA INDICATES SOME
AREAS COULD REACH 5 FT, BUT THEY ARE NOT EXPECTED TO LAST LONG
ENOUGH TO NECESSITATE A SCA ISSUANCE ATTM. BASED ON THE SOUTHERLY
FETCH, THIS MAY HAVE TO BE REVISITED. BY MONDAY NIGHT INTO
TUESDAY, THERE WILL BE SOME SLOW IMPROVEMENT AS HIGH PRESSURE
BUILDS IN AND PRECIP CHCS DECREASE. WEDNESDAY LOOKS TO BE DRY. THE
NEXT COLD FRONT APPROACHES ON THURSDAY.

&&

.RIP CURRENTS...
BASED ON THE LATEST DATA, WE ARE FCSTING A MODERATE RISK OF RIP
CURRENTS FOR SUNDAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR PAZ054-055-060>062-
     067>071.
NJ...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR NJZ001-007>010-012-
     015.
DE...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR DEZ001.
MD...FLOOD WATCH THROUGH LATE SUNDAY NIGHT FOR MDZ008.
MARINE...NONE.

&&

SYNOPSIS...IOVINO
NEAR TERM...ROBERTSON/MIKETTA
SHORT TERM...IOVINO
LONG TERM...GORSE
AVIATION...GORSE/NIERENBERG
MARINE...NIERENBERG
RIP CURRENTS...NIERENBERG

Hazardous weather outlook, Aug 13, 6:42 PM EST, 5 hours 18 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
742 PM EDT SAT AUG 13 2011

DEZ001-MDZ008-NJZ001-007>010-012-015-PAZ054-055-060>062-067>071-
142345-
NEW CASTLE-CECIL-SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-MIDDLESEX-
MERCER-CARBON-MONROE-BERKS-LEHIGH-NORTHAMPTON-CHESTER-MONTGOMERY-
BUCKS-DELAWARE-PHILADELPHIA-
742 PM EDT SAT AUG 13 2011

...FLOOD WATCH IN EFFECT THROUGH LATE SUNDAY NIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN DELAWARE...NORTHEAST
MARYLAND...CENTRAL NEW JERSEY...NORTHERN NEW JERSEY...NORTHWEST NEW
JERSEY...EAST CENTRAL PENNSYLVANIA...NORTHEAST PENNSYLVANIA AND
SOUTHEAST PENNSYLVANIA.

.DAY ONE...TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   FLOOD WATCH.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   FLOOD WATCH.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

DEZ002-003-MDZ012-015-019-020-NJZ013-016>023-027-142345-
KENT-INLAND SUSSEX-KENT MD-QUEEN ANNES-TALBOT-CAROLINE-
WESTERN MONMOUTH-SALEM-GLOUCESTER-CAMDEN-NORTHWESTERN BURLINGTON-
OCEAN-CUMBERLAND-ATLANTIC-CAPE MAY-SOUTHEASTERN BURLINGTON-
742 PM EDT SAT AUG 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL DELAWARE...SOUTHERN
DELAWARE...NORTHEAST MARYLAND...CENTRAL NEW JERSEY AND SOUTHERN NEW
JERSEY.

.DAY ONE...TONIGHT.

LOCALLY HEAVY RAIN IS POSSIBLE, WHICH MAY PRODUCE SOME FLOODING IN
AREAS OF POOR DRAINAGE AND ON ROADWAYS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

LOCALLY HEAVY RAIN IS POSSIBLE SUNDAY, WHICH MAY PRODUCE SOME FLOODING
IN AREAS OF POOR DRAINAGE AND ON ROADWAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

DEZ004-NJZ014-024>026-142345-
DELAWARE BEACHES-EASTERN MONMOUTH-ATLANTIC COASTAL CAPE MAY-
COASTAL ATLANTIC-COASTAL OCEAN-
742 PM EDT SAT AUG 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN DELAWARE...CENTRAL
NEW JERSEY AND SOUTHERN NEW JERSEY.

.DAY ONE...TONIGHT.

LOCALLY HEAVY RAIN IS POSSIBLE, WHICH MAY PRODUCE SOME FLOODING IN
AREAS OF POOR DRAINAGE AND ON ROADWAYS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THERE IS A MODERATE RISK OF RIP CURRENTS ON SUNDAY.

LOCALLY HEAVY RAIN IS POSSIBLE SUNDAY, WHICH MAY PRODUCE SOME FLOODING
IN AREAS OF POOR DRAINAGE AND ON ROADWAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

ANZ430-431-450>455-142345-
DELAWARE BAY WATERS NORTH OF EAST POINT NJ TO SLAUGHTER BEACH DE-
DELAWARE BAY WATERS SOUTH OF EAST POINT NJ TO SLAUGHTER BEACH DE-
COASTAL WATERS FROM SANDY HOOK TO MANASQUAN INLET NJ OUT 20 NM-
COASTAL WATERS FROM MANASQUAN INLET TO LITTLE EGG INLET NJ OUT 20 NM-
COASTAL WATERS FROM LITTLE EGG INLET TO GREAT EGG INLET NJ OUT 20 NM-
COASTAL WATERS FROM GREAT EGG INLET TO CAPE MAY NJ OUT 20 NM-
COASTAL WATERS FROM CAPE MAY NJ TO CAPE HENLOPEN DE OUT 20 NM-
COASTAL WATERS FROM CAPE HENLOPEN TO FENWICK ISLAND DE OUT 20 NM-
742 PM EDT SAT AUG 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS AND
DELAWARE BAY WATERS.

.DAY ONE...TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

In the hours before

Local storm report, Aug 13, 9:46 PM EST, 2 hours 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1046 PM EDT SAT AUG 13 2011

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

1015 PM     FLASH FLOOD      HAMBURG                 40.56N  75.98W
08/13/2011                   BERKS              PA   911 CALL CENTER

            ROADS FLOODED... RESIDENTIAL FLOODING... AND MINOR ROCK
            MUD SLIDES

&&

EVENT NUMBER PHI1100504

JRP

The radar

The Philadelphia radar (KDIX), 108 km away, was scanning. The volume nearest the first event began at 04:58 UTC.

Open the radar archive at this moment

Event by event

10 flash flood, 10 flood. Local standard time, as filed.

Flash Flood, Warren

When: August 14, 12:00 AM EST to 5:00 AM EST
Where: Warren County, 1.37 mi NNW of Phillipsburg to 0.86 mi WSW of Phillipsburg
Cause: Heavy Rain
Reported by: County Official
Coordinates: 40.719, -75.185

Thunderstorms with heavy downpours caused flash flooding of smaller streams and roadways in southern Warren County, mainly in Lopatcong, Greenwich and Pohatcong Townships, Alpha Borough and Phillipsburg. Event precipitation totals included 5.30 inches in Washington Township, 4.74 inches in Greenwich Township and 4.08 inches in Phillipsburg.

Flash Flood, Hunterdon

When: August 14, 12:00 AM EST to 5:00 AM EST
Where: Hunterdon County, 2.11 mi WNW of Holland to 0.24 mi SE of Frenchtown
Cause: Heavy Rain
Reported by: Mesonet
Coordinates: 40.589, -75.188

Thunderstorms with heavy downpours caused flash flooding of smaller streams and roadways in northwestern Hunterdon County, mainly in Alexandria, Bethlehem, Holland and Union Townships. Event precipitation totals included 5.23 inches in Bethlehem Township, 5.18 inches in Califon, 4.59 inches in High Bridge and 4.36 inches in Clinton.

Flash Flood, Somerset

When: August 14, 4:53 AM EST to 8:30 AM EST
Where: Somerset County, Belle Mead to 0.95 mi ESE of Neshanic
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.470, -74.650

Thunderstorms with heavy downpours caused flash flooding of smaller streams and roadways in southern Somerset County. The runoff from the heavy rain caused flooding along the Millstone River later that day. The Pike Run at Belle Mead was above its 7 flood stage from 653 a.m. EDT through 1046 a.m. EDT on the 14th. It crested at 7.25 feet at 930 a.m. EDT. Event precipitation totals included 5.86 inches in Montgomery Township, 4.61 inches in Hillsborough Township and 4.13 inches in Franklin Township.

Flash Flood, Salem

When: August 14, 8:00 AM EST to 2:00 PM EST
Where: Salem County, 2.91 mi SSW of Oakwood Beach to 3 mi SW of Hancocks Bridge
Cause: Heavy Rain
Property damage: $5.1 million
Reported by: Emergency Manager
Coordinates: 39.509, -75.533

Thunderstorms with repeated torrential downpours caused flash flooding with damaging effects across eastern Salem County, especially in Pittsgrove Township. A county state of emergency was declared. At least one water rescue was reported. Flooding was reported in Alloway, Pittsgrove, Elmer and Upper Pittsgrove Townships. Fourteen roadways, nine bridges and many culverts were damaged, most in Pittsgrove Township. Some families were evacuated in Pittsgrove Township around Palatine and Centerton Lakes. Two bridges washed away in the township on Greenville and Burlington Roads. It was expected to take six to twelve months for both bridges to be replaced. Two other township roadways remained closed into the 19th. In spite of being drained prior to the rain, Centeron Lake filled and flooded. A few homes were half submerged by flood waters along Palatine Lake. In Elmer, Elmer Lake also flooded. Event precipitation totals included 9.64 inches in Elmer and 5.89 inches in Woodstown.

Flood, Somerset

When: August 14, 8:30 AM EST to August 16, 11:30 PM EST
Where: Somerset County, 0.13 mi NNE of Rocky Hill to 1.55 mi NW of Harlingen
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.402, -74.629

Runoff from a series of thunderstorms from overnight on the 13th through the morning of the 16th caused poor drainage and river flooding, first along Pike Run in Belle Mead and then moderate flooding along the Millstone River.

The Millstone River at Griggstown and Blackwells Mills had moderate flooding. The Millstone River at Griggstown was above its 10 foot flood stage from 145 p.m. EDT on the 14th through 1230 a.m. EDT on the 17th. It crested at 13.99 feet at 415 a.m. EDT on the 15th. Farther downstream, the Millstone River at Blackwells Mills was above its 9 foot flood stage from 105 a.m. EDT on the 15th through 620 a.m. EDT on the 16th. It crested at 10.26 feet at 845 a.m. EDT on the 15th. The Pike Run at Belle Mead was above its 7 flood stage from 653 a.m. EDT through 1046 a.m. EDT on the 14th. It crested at 7.25 feet at 930 a.m. EDT.|Seventy-two hour event precipitation totals ending the morning of the 16th included 6.68 inches in Montgomery Township, 6.58 inches in Hillsborough Township 4.92 inches in Franklin Township and 4.75 inches in Bridgewater Township. .

Flash Flood, Gloucester

When: August 14, 9:00 AM EST to 2:00 PM EST
Where: Gloucester County, Williamstown to Cross Keys
Cause: Heavy Rain
Property damage: $100,000
Reported by: Emergency Manager
Coordinates: 39.680, -75.000

Thunderstorms with repeated torrential downpours caused flash flooding of roadways, streams and basements in the southern half of Gloucester County. Roadway flooding was reported in Pitman, Glassboro, Franklin, Washington and Monroe Townships. In Malaga (Franklin Township), U.S. Route 40 and New Jersey State Route 47 were flooded. The latter was still closed on the 15th. Conrail train service was stopped because of a sinkhole. In Glassboro, the foundation of a house on Deptford Drive collapsed. A motorist was rescued from flood waters on Delsea Drive (New Jersey State Route 47) near Clayton. In Clayton itself, a house became unstable because of its undermined foundation on North Main Street. In Williamstown (Monroe Township), flooding was reported along the Black Horse Pike (New Jersey State Route 42). Flooding also commenced along the Raccoon Creek. Event precipitation totals included 8.53 inches in Franklin Township and 5.92 inches in Woolwich Township.

Flash Flood, Atlantic

When: August 14, 9:00 AM EST to 11:00 AM EST
Where: Atlantic County, Wheat Rd to Five Pts
Cause: Heavy Rain
Reported by: Newspaper
Coordinates: 39.500, -74.970

Thunderstorms with torrential downpours caused street and small stream flash flooding along the northern tier of Atlantic County and affected Hammonton Township the hardest. Four roadways: Fairview Avenue, Orchard Street, Second Street and Railroad Avenue were closed. heavy rain also affected Folsom, Buena and Buena Vista Township. Event precipitation totals included 7.51 inches in Hammonton and 2.15 inches in Buena Vista Township.

Flash Flood, Cumberland

When: August 14, 9:00 AM EST to 2:00 PM EST
Where: Cumberland County, Stow Creek Lndg
Cause: Heavy Rain
Property damage: $20 million
Reported by: Emergency Manager
Coordinates: 39.450, -75.420

Thunderstorms with repeated torrential downpours caused flash flooding of roadways and streams in the western part of Cumberland County and affected Upper Deerfield Township and Bridgeton the hardest where two dams failed. This led to the evacuation of residents along the Cohansey River in Bridgeton, A county state of emergency was also declared. Over a dozen roadways were flooded and evacuations and water rescues occurred. Major roadways that were flooded and closed included State Routes 49 and 77. Many farm fields were submerged. Other hard hit municipalities included Greenwich, Stow Creek, Hopewell and Shiloh. Crops were also damaged, especially canning tomatoes. Damage was estimated at 20 million dollars.

In Upper Deerfield Township, the torrential downpours started a domino effect of dam failures along the Cohansey River. Seeley Lake was breached along Finley Road. The road was destroyed as the lake completely emptied. Downstream, the surge of water caused Sunset Lake to breach at West Park Drive in Bridgeton. This lead to the evacuation of approximately 150 residents along the Cohansey River within the city. A shelter was opened on Buckston Road. An approximately 1250 foot breach occurred along the river that flooded the Raceway within the Bridgeton City Park. The Cohanzick Zoo along the river was also flooded, but no animals were injured and the zoo itself was not seriously damaged. Flooding along Sunset Lake also led to the washout of a 75 foot by 100 foot section of Beebe Run Road within the city. Event precipitation totals included 10.82 inches in Upper Deerfield and 10.63 inches in Seabrook.

Flash Flood, Camden

When: August 14, 9:00 AM EST to 12:00 PM EST
Where: Camden County, 2.04 mi SSW of Winslow to 5.05 mi N of Sicklerville
Cause: Heavy Rain
Reported by: Newspaper
Coordinates: 39.622, -74.881

Thunderstorms with torrential downpours caused roadway, poor drainage and field flooding in the southern half of Camden County. Several roadways were flooded and closed, the most notable the White Horse Pike (U.S. Route 30). Event precipitation totals included 8.04 inches in Winslow Township and 5.41 inches in Berlin Township.

Flash Flood, Morris

When: August 14, 9:05 AM EST to 11:00 AM EST
Where: Morris County, 0.52 mi WSW of Lincoln Park to 0.64 mi ESE of Towaco Montville Arp
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.927, -74.309

Thunderstorms with heavy rain caused flash flooding of roadways and streams in northeastern Morris County during the morning of the 14th. The runoff flooding continued into the morning of the 16th. The East Ditch at Beaver Brook Road was above its 2.5 foot flood stage from 1005 a.m. EDT on the 14th through 817 a.m. EDT on the 16th. It crested at 3.13 feet at 1050 p.m. EDT on the 14th. Event precipitation totals included 4.45 inches in Long Hill Township, 4.08 inches in Denville, 3.79 inches in Morris Township, 3.75 inches in Chatham and 3.47 inches in Parsippany.

Flash Flood, Monmouth

When: August 14, 10:00 AM EST to 12:00 PM EST
Where: Monmouth County, Middletown to 0.4 mi SSE of Collingwood Park
Cause: Heavy Rain
Reported by: Newspaper
Coordinates: 40.400, -74.170

Thunderstorms with torrential downpours caused poor drainage and small creek flooding in central and eastern Monmouth Counties in Long Branch, Neptune, Ocean and Middletown Townships. Several major roads were flooded and closed and water rescues were performed. In Long Branch, five vehicles became stuck in flood waters. In Neptune Township, both New Jersey State Routes 33 and 35 flooded. In Ocean Township, three roadways flooded and in Middletown Township, southbound New Jersey State Route 35 was closed as was Palmer Avenue between New Jersey State Routes 35 and 36. Event precipitation totals included 5.55 inches in Ocean Township, 5.51 inches in Red Bank, 4.78 inches in Rumson, 4.66 inches in Long Branch, 4.29 inches in Middletown Township and 3.82 inches in Belmar.

Flood, Morris

When: August 14, 11:00 AM EST to August 16, 7:17 AM EST
Where: Morris County, 0.7 mi W of Lincoln Park to 0.58 mi SE of Lincoln Park Arpt
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.931, -74.313

Runoff from a series of thunderstorms from overnight on the 13th through the morning of the 16th caused poor drainage and creek flooding in northeast Morris County. The East Ditch at Beaver Brook Road was above its 2.5 foot flood stage from 1005 a.m. EDT on the 14th through 817 a.m. EDT on the 16th. It crested at 3.13 feet at 1050 p.m. EDT on the 14th. Seventy-two hour precipitation event totals through the morning of the 16th included 6.09 inches in Denville, 5.29 inches in Long Hill Township, 5.15 inches in Mine Hill Township, 5.01 inches in Parsippany, 4.75 inches in Morris Township, 4.54 inches in Chatham and 3.98 inches in Boonton.

Flood, Gloucester

When: August 14, 11:30 AM EST to 11:30 PM EST
Where: Gloucester County, 0.83 mi SE of Mt Royal to 1.05 mi W of Mt Royal
Cause: Heavy Rain
Deaths: 1 direct, 0 indirect
Reported by: Newspaper
Coordinates: 39.810, -75.211

The runoff from the heavy rain caused flooding in northern Gloucester County including the Mantua Creek basin. A 55-year-old woman drowned after she drove into the swollen creek. Her body was recovered on the 15th. In West Deptford, a 30 foot by 15 foot sink hole caused a basement masonry wall collapse on Ellwood Avenue. Near the Mantua Creek, the southern end of the Willow Woods Mobile Home Park on Crown Point Road (New Jersey State Route 44) was flooded and evacuated. The roadway remained closed into the 15th. Paradise Road in West Deptford was also closed. Event precipitation totals in the Mantua Creek drainage basin averaged 4 to 5 inches.

Flood, Gloucester

When: August 14, 2:00 PM EST to August 15, 8:07 AM EST
Where: Gloucester County, 1.68 mi W of Mullica Hill to 1.17 mi WNW of Mullica Hill
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 39.735, -75.261

The runoff from the heavy rain caused the greatest flooding along the Raccoon Creek since August 10, 1967. The Raccoon Creek at Swedesboro had its second highest crest on record since that date. The creek was above its 13 foot flood stage from 127 p.m. EDT on the 14th through 907 a.m. EDT on the 15th. It crested at 15.96 feet at 715 p.m. EDT on the 14th.

Flood, Salem

When: August 14, 2:00 PM EST to August 19, 12:45 AM EST
Where: Salem County, 2.54 mi SSW of Norma to 2.5 mi ENE of Greenville
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 39.465, -75.093

Runoff flooding from the torrential downpours persisted through the day on the 14th. Flooding then also started along the Maurice River. The Maurice River at Norma had major flooding and the second highest crest on record. The river at Norma was above its 4 foot flood stage from 105 a.m. EDT on the 15th through 145 a.m. EDT on the 19th. It crested at 6.33 feet at 125 p.m. EDT on the 16th.

Flood, Cumberland

When: August 14, 2:00 PM EST to August 19, 12:45 AM EST
Where: Cumberland County, 2.5 mi ENE of Rosenhayn to 0.24 mi ENE of Rosenhayn
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 39.496, -75.088

Runoff flooding from the torrential downpours persisted through the day on the 14th in western Cumberland County. Flooding then also started along the Maurice River. The Maurice River at Norma had major flooding and the second highest crest on record. The river at Norma was above its 4 foot flood stage from 105 a.m. EDT on the 15th through 145 a.m. EDT on the 19th. It crested at 6.33 feet at 125 p.m. EDT on the 16th.

Flood, Mercer

When: August 14, 5:00 PM EST to 8:30 PM EST
Where: Mercer County, 0.15 mi WSW of Trenton to 0.2 mi S of East Trenton
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.219, -74.752

Runoff from heavy rain that fell mainly during the first half of the day and early afternoon on the 14th led to flooding along the Assunpink Creek that evening. The Assunpink Creek in Trenton was above its 8.5 foot flood stage from 600 p.m. EDT through 1151 p.m. EDT on the 14th It crested at 8.82 feet at 930 p.m. EDT. Event precipitation totals included.

Flood, Monmouth

When: August 14, 9:18 PM EST to August 15, 3:35 AM EST
Where: Monmouth County, Squankum to 0.41 mi NNW of Allenwood
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 40.170, -74.150

Runoff from the heavy rain on the 14th caused flooding along the Manasquan River into the 15th. The Manasquan River at Squankum was above its 7.5 foot flood stage from 1018 p.m. EDT on the 14th through 435 a.m. EDT on the 15th. It crested at 7.67 feet at 1215 a.m. EDT on the 15th.

Flood, Atlantic

When: August 15, 1:31 PM EST to August 17, 3:15 PM EST
Where: Atlantic County, 0.95 mi WNW of Folsom to 0.49 mi NNW of Folsom
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 39.603, -74.867

Runoff from the torrential downpours, especially in the headwaters of the Great Egg Harbor River, led to record breaking and major flooding at the Folsom gage site on the 16th. The Great Egg Harbor River at Folsom was above its 6 foot flood stage from 231 p.m. EDT on the 15th through 415 p.m. EDT on the 17th. It crested at 8.18 feet at 530 a.m. EDT on the 16th.

Flood, Gloucester

When: August 16, 12:40 AM EST to 5:48 AM EST
Where: Gloucester County, 0.75 mi WNW of Mullica Hill to 1.99 mi NW of Mullica Hill
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 39.734, -75.243

More thunderstorms with heavy rain and extremely wet antecedent conditions caused additional flooding overnight on the 15th along the Raccoon Creek. County rainfall amounts averaged around one inch. The Raccoon Creek at Swedesboro was above its 13 foot flood stage from 140 a.m. EDT through 648 a.m. EDT on the 16th. It crested at 13.35 feet at 245 a.m. EDT.

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
Flood, Gloucester	2011-08-14	55	Female	Vehicle/Towed Trailer	Direct

What these are

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 New Jersey in 2011 Every state in 2011 This day in weather history Warnings in New Jersey, 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: 346052, 346053, 346109, 346261, 346140, 346275, 346316, 346323, 347883, 346134, 346321, 346139, 347737, 346317, 346318, 346319, 346143, 346322, 346320, 346324.