Flood in New Jersey, October 8 to 9, 2005

The combination of a very slow moving cold front and copious moisture from the remnants of Tropical Storm Tammy produced periods of very heavy rain across Hunterdon County on the 8th. Storm totals averaged from five to nine inches with the highest amounts in the northern part of the county. The heavy rain caused widespread poor drainage flooding and led to flooding along the South Branch of the Raritan River. In spite of the very heavy rain, there was no flooding along the Delaware River. The South Branch of the Raritan River at High Bridge was above its 10 foot flood stage from 5 a.m. EDT through 845 a.m. EDT on the 9th. It crested at 10.11 feet at 6 a.m. EDT. Farther downstream at Stanton, the South Branch of the Raritan River was above its 6 foot flood stage from 1207 a.m. EDT through 441 a.m. EDT on the 9th. It crested at 8.51 feet at 246 a.m. EDT. Storm totals included 9.07 inches in Califon, 7.18 inches in Flemington, 6.80 inches in Clinton, 6.68 inches in Stockton and 5.88 inches in Wertsville. The flooding on the 8th and 9th and the subsequent flooding during the upcoming week damaged over 2,700 single family homes, over 640 apartment units and 220 businesses throughout the state of New Jersey. The cold front moved from near Pittsburgh, Pennsylvania at 8 p.m. EDT on the 7th, to the Susquehanna Valley in Pennsylvania at 2 a.m. EDT on the 8th, to the Poconos and Berks County in Pennsylvania and just west of Chesapeake Bay in Maryland at 8 a.m. EDT on the 8th. The cold front stalled as waves of low pressure road northeast along it. At 2 p.m. EDT on the 8th, the cold front just edged into northwestern New Jersey and the Philadelphia northwest suburbs and was still west of Chesapeake Bay in Maryland. At 8 p.m. EDT that evening the cold front barely moved into the Philadelphia New Jersey suburbs and the Delmarva Peninsula. The cold front and waves of low pressure cleared the Delaware and New Jersey coasts between Midnight EDT and 2 a.m. EDT on the 9th. The slow movement and stalling coupled with an unstable air mass and tropical moisture associated with Tammy helped enhance the torrential downpours. The flooding would have been even worse if not for the unseasonably dry weather that preceded this event from the middle of August.