Flood — Hunterdon, New Jersey

2011-09-08 to 2011-09-10 · near Lambertville, Hunterdon, New Jersey

Event narrative

One hundred and seven homes were damaged by the flooding associated with the remnants of Lee in Hunterdon County. Three homes suffered major damage, eighty-nine minor damage and fifteen more were affected by flood waters. The New Hope-Lambertville Bridge crossing the Delaware River was closed after a large tree wedged underneath it. The bridge was re-opened on the 9th.

The Delaware River at Frenchtown had moderate flooding, its 8th highest crest on record and highest crest since June 29, 2006. It was above its 16 foot flood stage from 216 a.m. EDT on the 8th through 200 a.m EDT on the 10th. It crested at 19.02 feet at 545 a.m. EDT on the 9th. Farther downstream, the Delaware River at Stockton had moderate flooding, its 10th highest crest on record and highest crest since June 29, 2006. It was above its 18 foot flood stage from 240 a.m. EDT on the 8th through 337 a.m. EDT on the 10th. It crested at 21.76 feet at 645 a.m. EDT on the 8th. Farther downstream, the Delaware River at Lambertville had major flooding, its 11th highest crest on record and highest crest since June 29, 2006. It was above its 13 foot flood stage from 358 a.m. EDT on the 8th through 1215 a.m. EDT on the 10th. It crested at 16.14 feet at 700 a.m. EDT on the 8th.

The South Branch of the Raritan River at High Bridge had minor flooding and was above its 10 foot flood stage from 727 a.m. EDT through 704 p.m. EDT on the 8th. It crested at 10.95 feet at 1215 p.m. EDT. Farther downstream, the South Branch of the Raritan River at Stanton had moderate flooding. It was above its 8 foot flood stage from 352 a.m. EDT on the 8th through 242 a.m. EDT on the 9th. It crested at 11.98 feet at 830 a.m. EDT on the 8th.

The entire event precipitation totals included 7.80 inches in Clinton, 7.20 inches in Kingwood, 7.18 inches in High Bridge, 7.15 inches in Califon, 6.21 inches in Pittstown and 6.19 inches in Flemington.

Wider weather episode

The remnants of Tropical Storm Lee that interacted with a stalled frontal boundary produced several days with periods of heavy rain across New Jersey from the 5th into the 8th. Event precipitation totals averaged 3 to 8 inches, with lesser amounts in Atlantic, Cape May and eastern Ocean Counties. The heavy rain caused renewed flooding mainly to the west and northwest of the New Jersey Turnpike corridor with mainly moderate flooding along the main stem of the Delaware River with moderate to major flooding in the Passaic and Raritan Basins. Crests were higher on the Delaware River than with Irene as many sites had their highest crests since late June of 2006. The crests along the Delaware River were 2 to 4 feet higher than what occurred during Irene. Elsewhere, nearly all crests were lower than what occurred during Irene. Most of the reported damage occurred in counties bordering the Delaware River as 2 homes were destroyed, 24 suffered major damage, 249 suffered minor damage and 28 others were affected. There were approximately 1,000 people evacuated; other than Morris County, most of the other evacuations occurred in counties bordering the Delaware River. Throughout the state 162 roads were closed due to flooding. The freshwater surge also helped cause moderate tidal flooding along tidal sections of the Delaware River. Preliminary statewide damage was estimated at around 11.5 million dollars. The heavy rain and flooding also took its toll on crops. Farmers reported up to seventy-five percent losses of their pumpkin and tomato crops.

The combination of fresh water runoff and a weak southerly flow produced moderate tidal flooding during the evening high tide cycles from the 7th through the 9th and minor tidal flooding with all of the other high tide cycles from the evening of the 6th through overnight on the 11th. The highest tides occurred during the evening high tide cycle on the 8th. In Burlington County, tidal flooding was reported in Delran and Cinnaminson. In Camden County, the Admiral Wilson Boulevard flooded as did South Park Drive along the Cooper River in Collingswood. In Gloucester County, New Jersey State Route 44 was closed near the Repaupo Creek.

The evening high tide on the 8th in Philadelphia reached 9.41 feet above mean lower low water. Moderate tidal flooding starts at 9.2 feet above mean lower low water. The high tide in Burlington City (Burlington County) reached 10.51 feet above mean lower low water. There is no current categorical tide gage information for this site. While the worst tidal flooding occurred along tidal sections of the Delaware River, widespread minor tidal flooding also occurred in upper Delaware Bay. The high tide reached 7.56 feet above mean lower low water at Reedy Island Delaware (Minor tidal flooding starts at 7.2 feet above mean lower low water).

Tropical Storm Lee made landfall in Louisiana during the morning of the 4th and moved slowly northeast. An approaching cold front from the Mississippi Valley reached Lee by the morning of the 5th and transformed it to an extratropical system on the 5th in Mississippi. The same cold front acted as a conduit for Lee's moisture farther to the northeast. Showers and thunderstorms from that approaching cold front arrived during the evening and overnight on the 5th and set off the first round of flash flooding rains in Northwest New Jersey. The front then stalled just south of Delmarva on the 6th. A relative lull in the rain then occurred during the morning of the 6th. As the front started to back north into New Jersey as a warm front later in the day on the 6th, more bands of heavier rain returned that afternoon and particularly that evening. A blocking weather pattern then moved the frontal boundary little from the morning of the 7th into the morning of the 8th over New Jersey. Most of the precipitation on the 7th remained west of the state. Heavier rain formed north of the stalled frontal boundary in central and northern New Jersey during the evening of the 7th. A band of showers and thunderstorms with heavier rain then moved across the state during the first half of the day on the 8th. The frontal boundary started to drift offshore on the 8th and little if any Lee related precipitation fell in the state after that morning.

View location on OpenStreetMap → (40.3700, -74.9300)

Source: NOAA Storm Events Database, event_id 349900. Narrative written by the NWS forecast office that issued the report.