Flash Flood in New Jersey, October 8, 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 Warren County from the evening of the 7th into the evening of the 8th. Storm totals averaged from seven to ten inches. The heavy rain caused widespread poor drainage flooding as well as flooding along the creeks in the county. The greatest roadway flooding was reported in Blairstown. In spite of the heavy rain, the Delaware River did not flood. While the Delaware River did not flood, the large within bank rise of the river disturbed coal ash deposits at the bottom of the river and caused arsenic levels to rise above acceptable levels for two days. Both the Pohatcong and Lopatcong Creeks flooded within the county. In Phillipsburg, in addition to the Pohatcong Creek flooding, a retaining wall collapsed. The heavy rain contributed to the death of a two-year-old boy during a traffic accident on Interstate 80 in Knowlton. Storm totals included 10.30 inches in Columbia, 10.04 inches in Mountain Lake, 9.79 inches in Blairstown and 8.11 inches in Stewartsville. 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.