New storm could threaten Sandy-damaged beaches
The lack of protective dunes and damage to sea walls could lead to lowland flooding near the coast.
Mon, Nov 05, 2012 at 10:12 AM
Mantoloking, New Jersey. 'Before' image captured by Google and 'After' image captured by NOAA's National Geodetic Survey. Note the new inlet created by Hurricane Sandy-caused storm surge. (Photo: Google and NOAA/OurAmazingPlanet)
With coastal communities in New York and New Jersey still reeling from the devastation caused by Hurricane Sandy, the last thing the area needs is another storm. But that's exactly what it might get.
A nor'easter is predicted to potentially hit the East Coast on Nov. 7, and beach erosion experts are concerned about further damage to shorelines devastated by Sandy.
As Sandy came ashore, its record surge and pounding waves tore apart or eroded hundreds of miles of dunes and protective sea walls along the East Coast. Hundreds of homes and buildings, which also provided some protection, were destroyed.
The lack of protective dunes and damage to sea walls could lead to lowland flooding near the coast, depending on the wind direction and storm surge from the new storm, even one that isn't expected to approach Sandy's strength.
"The beaches and sand dunes are the first line of defense for coastal communities against storm surge and waves. They're going to take the first brunt of the storms," said Hilary Stockdon, a research oceanographer with the U.S. Geological Survey in Reston, Va. [Infograpic: Timeline of Sandy's Week of Destruction]
First line of defense
Many of the sandy beaches along the Atlantic Coast have become increasingly vulnerable to significant impacts due to erosion during past storms, including Hurricanes Ida (2009) and Irene (2011), as well as large storms in 2005 and 2007, according to the USGS.
Stockdon said Sandy caused extensive erosion to beaches and dunes. The USGS and other agencies are now running aerial and ground surveys to assess the damage.
"There are dunes that have been eroded away completely, so now their protection is gone," Stockdon told OurAmazingPlanet. "That will make these communities more vulnerable to future storms that may not be as strong."
Quick repair and restoration of the coast could be essential to minimizing damage from future storms, whether the one currently brewing or any others that could develop later in the winter. In New York, the Department of Environmental Conservation is issuing emergency permits for storm-related repairs in coastal areas and wetlands.
Natural repair weakened
Farther north, front-end loaders are already pushing sand back onto the beach, said Greg Berman, a coastal geologist with the Woods Hole Institute Sea Grant program in Falmouth, Mass.
During powerful storms like Sandy, surging waves throw sand up and over the beach, where it remains stuck. The beach can't restore itself without access to sand. However, this is also a natural process; beaches aren't stationary, and their location migrates with time, Berman told OurAmazingPlanet. "When you push it back onto the beach, you're circumventing that migration, and it gets harder and harder to do over time," he said.
Sandy's late October arrival also increased coastal vulnerability by removing sand that had been naturally stored offshore for summer beach replenishment, Berman said. During the winter, sand is stored in sandbars and comes back in the summer. "After Sandy, instead of going into a nor'easter system at our best, we're going into it at a weakened condition," Berman said.
Election night downpour
The new storm's path is predicted to move from the Southeast Tuesday night into New Jersey on Wednesday, said Brian McNoldy, a weather researcher at the University of Miami.
"It looks like your average Nor'easter that comes in off the coast," he told OurAmazingPlanet. The forecast is from the same European computer model that eyeballed the projected path of Hurricane Sandy. Its precise strength and route is still uncertain, but the storm will be nowhere near the level of Sandy's tropical-force winds.
Coastal communities hit by the Frankenstorm will see strong onshore winds and waves, though whether the storm will come on land or stay out at sea is still uncertain.
"I think by far the worst impact will be the coastal flooding and erosion, and that's a concern regardless of how far off the coast it is. You'll get pretty strong winds and enhanced swells and waves. I think that's looking pretty certain," McNoldy said.
History of erosion
Beaches on the East Coast have been steadily eroding for 150 years, according to a USGS report released in February 2011. On average, the beaches in New England and the Mid-Atlanticare losing about 1.6 feet (0.5 meters) per year. The worst erosion case was about 60 feet (18 m) per year at the south end of Hog Island, in southern Virginia.
According to New York Gov. Andrew Cuomo's office, Rockaway Beach (on a peninsula in New York City's borough of Queens) was almost completely washed away and the boardwalk was destroyed. Jones Beach (a barrier island off Long Island) was overwashed by ocean. Gilgo Beach's dune system (on Long Island) was almost destroyed, and Ocean Parkway (which runs along the southern end of Long Island) was overwashed. [Video: Sandy's Flooding Aftermath]
In New Jersey, Long Beach Island, a barrier island and popular vacation spot, sustained severe damage, with boats and cars tossed into streets and several feet of sand piled against houses. The island was evacuated before the storm.
Before Sandy's landfall, USGS scientists predicted different types of coastal erosion. Collision is when waves attack the base of dunes and cause erosion. Overwash is when waves and water from storm surges rush over dunes and carry sand farther inland. Inundation is when the storm surge floods the beach and dunes.
Along the Jersey Shore, where Sandy would make landfall, nearly all — 98 percent — of the coast was very likely to experience beach and dune erosion, 54 percent was very likely to overwash, and 21 percent was very likely to be inundated
The south shore of Long Island, including Fire Island National Seashore, was very likely to experience beach and dune erosion along 93 percent of the coast and overwash was very likely to occur along 12 percent of the sandy coast.
On the Delmarva Peninsula, which includes Delaware and parts of Maryland and Virginia, 91 percent of the sandy coast was expected to see beach and dune erosion, 55 percent was very likely to overwash, and there was a high likelihood of inundation on 22 percent.
Reach Becky Oskin at email@example.com. Follow her on Twitter @beckyoskin. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.
Related on OurAmazingPlanet:
Related Hurricane Sandy story on MNN: 7 memorable vidoes of Hurricane Sandy and its aftermath