Measuring Sandy's impact
Sandy, which began its impact on the region as a hurricane and made landfall five miles southwest of Atlantic City as a coastal storm, produced intense rainfall, high winds and near-record tidal flooding.
The high water mark reached during Sandy at Atlantic City’s Steel Pier on the oceanfront was 8.9 feet above mean low water, or the average lowest tide, just shy of the record 9 feet during the December Storm of 1992, which left a similar devastating impact along southern New Jersey’s coastline.
Had Sandy struck New Jersey 50 years ago, during the time of the March Storm of 1962, the water level would have been 8.3 feet, slightly higher than the 8.2 feet measured at Steel Pier, before it was destroyed by a wayward barge.
Sandy’s impact on the shoreline south of Long Beach Island, in effect, wasn’t too much worse than from December Storm of 1992, Farrell said.
But numerous houses on the barrier islands, including in Ventnor, Atlantic City, Margate, Brigantine and Ocean City, had flooding damage during Sandy, when they didn’t have flooding from any previous storm on record.
At the Atlantic County Utilities Authority wastewater treatment plant on Route 30, tidal records date to the March 1962 storm, where workers measured the maximum height at 9.6 feet, ACUA President Rick Dovey said. The water level during Sandy was slightly less, at 9.5 feet, Dovey said.
Sandy tied a record at landfall for the lowest measured barometric pressure in the United States north of Cape Hatteras, N.C., equal to that of the pressure in the 1938 Long Island Express hurricane. In Atlantic City, though, unofficial measurements at Steel Pier recorded the air pressure, which is an indicator of a storm’s strength, at 945.2 millibars, shattering the record of 961 millibars set in 1932.
Nearly a foot of rain fell in parts of Cape May County, with Stone Harbor recording 12.71 inches during Sandy, according to the Office of the State Climatologist.
State Climatologist David Robinson also noted in his monthly report that Sandy’s inland wind impacts were exceptional.
“It is likely that inland winds had never been as strong or of a multihour duration in the modern era across central and northern areas; perhaps not since an 1821 hurricane ravaged the region,” Robinson wrote. “While precipitation was not excessive over most of the state, the far southern coastal region had a deluge that statistically happens once every 200 years.”
Another measure of Sandy’s strength was the wave run-up, or how far the water from waves and surf wash up from where they crash.
Richard Stockton College professor and coastal sciences researcher Stewart Farrell, who has worked as a consultant for multiple New Jersey coastal municipalities as well the state and federal government regarding beach profiles and dune engineering, finished two weeks ago collecting data from 105 sites along New Jersey, which will provide critical data to scientists revising flood zone maps.
Among the findings were that the wave run-up in Atlantic City was 14.5 feet, leaving the tide debris line along the crest of the city’s controversial 14.75-foot dunes. The wave run-up in devastated Monmouth County beach towns, which received the worst of Sandy’s storm surge and wave heights, was 34.5 feet, Farrell said.
“The dunes in Atlantic City were just big enough during Sandy,” Farrell said.
Had Sandy made landfall near the mouth of the Delaware Bay, a scenario that had been considered as highly likely by forecasters before the storm, the storm surge and waves would have quickly overwhelmed Atlantic City’s dunes, devastating the city.
“Atlantic City would have had a substantial amount of redecoration for each of the casinos, all of the beach sand in Pacific Avenue and chunks of Boardwalk would go right through the front door of all the casinos,” Farrell said.