Coastal Flood — Southwest Suffolk, New York

2017-10-30 · Southwest Suffolk, New York

Event narrative

The USGS tidal gauge in Great South Bay at Lindenhurst recorded a peak water level of 3.7 ft. MLLW at 454 am EST. The moderate coastal flood threshold of 3.6 ft. MLLW was exceeded from 424 to 536 am EST. The USGS tidal gauge in Great South Bay at Sayville recorded a peak water level of 3.9 ft. MLLW at 642 am EST. The moderate coastal flood threshold of 3.5 ft. MLLW was exceeded from 448 to 854 am EST. Moderate inundation of around 2 feet was reported along numerous waterfront roads and properties in Bayshore, West Babylon, Babylon, Lindenhurst, Blue Point, Patchogue, and Sayville. In Brookhaven, major inundation of 3 to 5 feet occurred at Squassux Landing Marina along Carmans River, sinking some boats. In Bellport, moderate inundation of 1 to 3 feet was observed at Bellport Marina, sinking a number of boats and flooding a few waterfront business.

The USGS tidal gauge in Watch Hill on Fire Island recorded a peak water level of 4.2 ft. MLLW at 718 am EST. This exceeded the major coastal flood threshold of 4.5 ft. MLLW. The moderate coastal flood threshold of 3.6 ft. MLLW was exceeded from 512 to 924 am EST. On Fire Island, extensive damage in excess of $3 million occurred at Davis Park Marina due to a combination of 2 to 3 feet of inundation, long shore currents, and 1 to 2 feet of wave action.

The coastal flooding thresholds were established by the National Weather Service, based on impact analysis and collaboration with the USGS and local emergency management.

Wider weather episode

A southern low rapidly intensified as it raced up the East coast Sunday, and over NYC Sunday Night. This low brought a rapid onset but relatively brief period of SE gale to storm force winds Sunday evening, shifting to WNW gales Monday morning. High seas built into Monday Morning.

Moderate coastal flooding occurred along the Great South Bay with the Monday morning high tide. Surge continued to increase well after peak onshore winds, with water levels receding briefly or not at all during low tide. The westerly wind shift helped slosh surge into eastern portions of the Great South Bay, with recession below flood levels taking several hours after high tide.

Source: NOAA Storm Events Database, event_id 725426. Narrative written by the NWS forecast office that issued the report.