Hurricane Sandy devastated much of the Mid-Atlantic Coast
this week with ferocious winds, record-setting storm surge and destructive
waves. While the economic toll from this disaster could total up to $50 billion
(Huffington Post, November 2, 2012), the staggering human loss has made this
storm a catastrophe. The latest death toll has risen to 80 fatalities in the
U.S., including 38 victims in New York City (New York Times, November 2, 2012.)
The record-breaking storm surge, which smashed ashore most
viciously in New Jersey and New York, caused many of these fatalities and much
of the damage. On Staten Island, for example, a two-year-old boy drowned when
the surge swept him from his mother’s arms (New York Times, November 1, 2012).
Photos of the surge damage depict homes which were either smashed to pieces or
floated off their foundations, as well as debris-covered streets, which were
also buried under feet of sand.
Preliminary surge observations have provided a maximum surge
level of 14.6 feet at Bergen Point, NJ (www.abcnews.go.com.)
However, surge levels were devastatingly high all along the New Jersey Coast,
in the metropolitan New York City area, on Long Island, and even in coastal New
England.
Battery Park, NY, located at the southern tip of Manhattan
Island, set a new record high water level of 17.33 feet above the station
datum, a vertical reference line for measuring water heights. This water level
was reached through a combination of high astronomical tides and a 9.23-foot
storm surge, which is the storm-driven water height above normal tide levels.
Such high water levels enabled salt water to pour over sea walls in Lower
Manhattan and inundate the subway system under many feet of water.
Sandy’s water level at Battery Park broke Hurricane Donna’s
(1960) previous high-water record by more than four feet. It is also
interesting to note that Hurricane Sandy’s massive surge comes just 14 months
after Hurricane Irene inundated much of the coastline, producing the fourth
highest water level of all time at Battery Park.
These surge observations will be incorporated into SURGEDAT,
the world’s most comprehensive storm surge archive. This dataset has been
developed through funding made possible by NOAA-funded SCIPP, the Southern
Climate Impact Planning Program. SURGEDAT has identified the peak storm surge
level in more than 450 global surge events since 1880, including more than 300
events in the United States. Recently this dataset was expanded to include the
entire inundation footprint for more than 240 U.S. surge events. These
footprints contain more than 6,100 historic storm surge observations in the
United States.
These data are useful for coastal decision makers, emergency
management professionals, insurance professionals, as well as coastal
scientists and storm surge modelers. For example, such data are very useful for
risk-assessment studies, which identify critical inundation thresholds, such as
the 100-year storm surge level for a given location. These data are also useful
to validate storm surge models, which often need actual observed data to
validate model runs.
Prior to Sandy’s landfall, SCIPP mapped out hurricane paths
and inundation envelopes for five previous hurricanes that generated storm
surges in the New York City area. These maps provided historical context as
Sandy approached. One of the key messages of these historical maps is that
Sandy’s storm track was unprecedented along the Mid-Atlantic Coast. These maps
also provided evidence that the area of coastline near New York City is very
effective at funneling in storm surge, presumably because water gets trapped in
this area. Storm surge levels during the 1944 Hurricane and Hurricane Donna
(1960) were higher in this region than other areas along the coast- a
realization that hopefully encouraged many people in the metro New York area to
evacuate Sandy’s devastating storm surge.
