Coastal Flood — Washington, Rhode Island

2012-10-29 · Washington, Rhode Island

Event narrative

The Rhode Island coastline in Washington County, stretching from Westerly to Narragansett was devastated by coastal flooding associated with Superstorm Sandy. Much of the coastline is composed of barrier beaches, very shallow strips of land with the Atlantic Ocean on the south side and ponds on the north side. As Sandy moved northward up the eastern seaboard, it built the seas over several days and as it turned to the west, eventually making landfall in New Jersey, these high seas (measured at 31 feet on the Block Island buoy) hit the Rhode Island coast over multiple tide cycles. This continuous battering of high seas, washed beaches inland exposing bedrock and other sand dune anchors. Some houses on the beach were washed clean off their foundations. Others with breakaway construction on the ground level indeed broke away with ocean water flooding the oftentimes now finished ground levels through to the other side of the house. There were four beaches/areas that were particularly hard hit, further details on each of them follow.

Roy Carpenter's Beach in South Kingstown - On a beach that previously had a wide expanse of sand, 50 feet of beach grass, a parking lot, and a road between the Atlantic and a beach cottage community, cottages are now being threatened by waves. Three cottages were washed off their foundations and one was left teetering on its foundation. Others slid into the water where the beach had been completely eroded. Dozens of other cottages were damaged. As much as 50 feet of beach were destroyed or eroded away.

Green Hill Beach in South Kingstown - All the sand dunes on Green Hill Beach were washed away. The ground level of the Green Hill Beach Club was completely washed away, with only pillars left to hold the second floor up.

Charlestown Breachway in Charlestown - Charlestown Beach Road was nearly impassable thanks to beach sand three to four feet deep that had washed over the road. The guard shack at the breachway was pushed all the way through the parking lot to Ninigret Pond on the north end of the parking lot. The three main coastal roads, Charlestown Beach Road, East Beach Road, and West Beach Road were all closed to all but local residents. Year round residents along these roads were asked to evacuate and while a few stayed, most did evacuate and none stayed in the Charlestown Beach area. Most of the houses that flooded were summer homes and unoccupied. However, houses on the north shore of Ninigret Pond were inundated with storm surge.

Water overtopped the seawall across the breachway at East Beach even three hours after the Monday morning high tide. The parking lot at the Quonochantaug Breachway fishing area was flooded with two feet of water at high tide Monday morning and was still flooded three hours later.

Misquamicut Beach in Westerly - This area was asked to evacuate as well and remained evacuated through at least Tuesday. Sand dunes missing from the beaches washed through houses onto Atlantic Avenue, normally some 200 feet from the ocean, piling up to six feet high in spots, completely blocking Atlantic Avenue. The Andrea Hotel and Resort's beachside patio was pushed through the building on ocean waters. Six feet of sand was washed into Maria's Seaside Cafe and crashing ocean waves caused significant structural damage. Several other beach side businesses sustained extensive damage.

Other damage from Washington County included:

- In Narragansett, pounding waves blew out the windows at the Coast Guard House restaurant, flooding the inside. In addition, 20,000 yards of sand were removed from Narragansett Town Beach by the storm. Waves also battered several buildings and tore up a beach parking lot.

- 19 water systems in Rhode Island had to issue boil water advisories after the storm left low or no pressure in those systems, making them susceptible to contamination.

- In Watch Hill, Main and Bay Streets were flooded with ocean water.

Wider weather episode

Superstorm Sandy, a hybrid storm with both tropical and extra-tropical characteristics, brought high winds and coastal flooding to southern New England. Easterly winds gusted to 50 to 60 mph for interior southern New England; 55 to 65 mph along the eastern Massachusetts coast and along the I-95 corridor in southeast Massachusetts and Rhode Island; and 70 to 80 mph along the southeast Massachusetts and Rhode Island coasts. A few higher higher gusts occurred along the Rhode Island coast. A severe thunderstorm embedded in an outer band associated with Sandy produced wind gusts to 90 mph and concentrated damage in Wareham early Tuesday evening,

a day after the center of Sandy had moved into New Jersey. In general, moderate coastal flooding occurred along the Massachusetts coastline, and major coastal flooding impacted the Rhode Island coastline. The storm surge was generally 2.5 to 4.5 feet along the east coast of Massachusetts, but peaked late Monday afternoon in between high tide cycles. Seas built to between 20 and 25 feet Monday afternoon and evening just off the Massachusetts east coast. Along the south coast, the storm surge was 4 to 6 feet and seas from 30 to a little over 35 feet were observed in the outer coastal waters. The very large waves on top of the storm surge caused destructive coastal flooding along stretches of the Rhode Island exposed south coast.

Sandy grew into a hurricane over the southwest Caribbean and then headed north across Jamaica, Cuba, and the Bahamas. As Sandy headed north of the Bahamas, the storm interacted with a vigorous weather system moving west to east across the United States and began to take on a hybrid structure. Strong high pressure over southeast Canada helped with the expansion of the strong winds well north of the center of Sandy. In essence, Sandy retained the structure of a hurricane near its center (until shortly before landfall) while taking on more of an extra-tropical cyclone configuration well away from the center. Sandy's track was unusual. The storm headed northeast and then north across the western Atlantic and then sharply turned to the west to make landfall near Atlantic City, NJ during Monday evening. Sandy subsequently weakened and moved west across southern Pennsylvania on Tuesday before turning north and heading across western New York state into Quebec during Tuesday night and Wednesday.

In Southern New England, Rhode Island was hardest hit. A peak wind gust of 86 mph occurred in Westerly, and nearly the entire Rhode Island shoreline experienced moderate to major coastal flooding. Numerous power outages occurred with winds gusting to 60 mph over the interior and to 80+ mph along the south coast. Major coastal flooding struck the Rhode Island ocean exposed south coast during the Monday evening high tide. This storm tide, especially destructive across shorelines in Westerly, Charlestown, South Kingston, Narragansett, and Block Island, rivaled the impact from Hurricane Bob in 1991. Along the Rhode Island south coast, the damaging coastal flooding was fueled by a storm surge around 5 feet and waves of 30+ feet that propagated on a long fetch into Block Island and Rhode Island Sounds. A survey of impact along Misquamicut Beach revealed an inundation extent consistent with the upper boundary of a category 1 Hurricane and very severe erosion. It should also be noted that the previous high tide during Monday morning produced minor to moderate impacts along the Rhode Island coast and likely weakened dunes and other coastal structures in advance of the more destructive Monday evening high tide.

Source: NOAA Storm Events Database, event_id 416567. Narrative written by the NWS forecast office that issued the report.