Flash Flood — Somerset, New Jersey

1996-10-19 · near Countywide, Somerset, New Jersey

Wider weather episode

Rain, very heavy at times around noon on the 19th caused widespread and severe flooding throughout Somerset County. For the major rivers, most of the crests were the second highest on record and represented a 25 to 50 year flood. The all-time record crests occurred with Tropical Storm Doria in August 1971. A state of emergency was declared and total damage was estiamted at $31 million dollars. Many motorists were stranded. Parts of Interstate 287, United States Routes 202 and 206, New Jersey State Route 22 and County Route 610 were closed as long as the afternoon of the 20th. The Blackwell Mills and Griggstown Causeways remained closed until the 22nd in Franklin Township. The worst damage was in Manville (The confluence of the Raritan and Millstone Rivers.) and Bound Brook (The Raritan River). In Manville 200 persons were evacuated, 160 spent the night in a shelter. The Lost Valley area was hit the hardest especially the homes on Huff, Boesel and Manville Avenues. A house on Huff Avenue collapsed. In Bound Brook, 115 persons were evacuated. Seventy-five homes and seventeen businesses were damaged. Fourteen of seventeen homes on Main Street were uninhabitable. Three feet of river water extended from Main to Hamilton Streets.Other hard hit townships included Hillsborough. During the height of the heavy rain, the town was completely shut off. The East Brook overflowed and made the center of town impassable. Clogged catch basins enhanced the flooding. Emergency personnel responded to over 120 requests. Evacuations occurred in Green Brook Township and North Plainfield Borough and along the Delaware and Raritan Canal. In Branchburg, evacuations were ordered near New Jersey State Route 28 along the South Branch of the Raritan River. The Watchung Lake in Watchung overflowed. In Warren Township, several roads along the Passaic River were closed. In Bernardsville, the Mine Brook flooded the Old Mill Inn. In Montgomery Township, the 176-year-old Dead Tree Run Bridge was severely damaged. The Pine Brook flooded over it. About ten roads within the township were impassable making access into or out of the town nearly impossible. In Somerville, roof damage occurred to both the Van Derveer School and the YMCA. The North Branch of the Raritan River had a RECORD BREAKING CREST at Raritan of 15.5 feet at 1130 p.m. EDT on the 19th. In Far Hills, the River crested at 5.9 feet at 630 p.m. EDT represented a 18 year recurrence interval. The Millstone River at Blackwell Mills crested at 15.6 feet at 5 a.m. EDT on the 20th, the third highest crest on record. This represented a 20 year recurrence interval. The main stem Raritan River at Manville crested at 22.4 feet at 415 a.m. EDT on the 20th, the second highest on record. The record is 23.8 feet set on August 28, 1971. The Raritan River at Bound Brook crested at 35.6 feet, 2nd highest on record at 615 a.m. EDT on the 20th. The record is 37.5 feet also set on August 28, 1971. The latter two locations flooding represent about a 50 year recurrence interval. No serious injuries were reported. Storm precipitation totals included 7.05 inches in Pottersville, 6.93 inches in Far Hills, 6.4 inches in Basking Ridge, 6.1 inches in Somerville, 5.9 inches in Watchung, 5.87 inches in Martinsville, 5.7 inches in Bound Brook, 4.88 inches in Bridgewater and 4.76 inches in Montgomery.

Source: NOAA Storm Events Database, event_id 5577594. Narrative written by the NWS forecast office that issued the report.