Storm Summary for Superstorm Sandy
Preliminary estimates suggest Sandy was the second-costliest Atlantic hurricane on record (behind Hurricane Katrina). More than 120 people perished from the effects of Sandy, approximately 24 in the Mount Holly County Warning Area (CWA) alone. Dollar estimates of damage to homes and infrastructure range into the billions of dollars in New Jersey, with over nine million dollars of damage reported in Delaware.
Hurricane Sandy was the eighteenth named storm of the 2012 Hurricane Season, and the tenth hurricane. A surface high pressure blocking pattern over northern New England coupled with a strong mid-level trough moving east from the Midwest were the two primary features which established Sandy's eventual landfall trajectory into southern
New Jersey on the evening of October 29th.
The National Hurricane Center (NHC) classified Tropical Depression 18 as a tropical storm on Monday October 22nd at 11 am EDT when it was located in the Caribbean Sea (Fig 1). After slow movement for several days, a northward motion began which increased as Sandy reached category one hurricane strength at 11 am on October 24th.
Figure 1: Track of Sandy source: Weather Underground
A landfall occurred in Jamaica at 3:20 pm that afternoon. Sandy then strengthened overnight
to category two strength at 110 mph before making another landfall in Cuba (Fig 1). Sandy
continued a northward movement through the Bahamas before making a northwest then west
turns due to the blocking pattern and approaching trough, with some weakening followed
by fluctuations in strength. Landfall occurred Monday evening just south of Atlantic City
at 8 pm (fig 1). After 500 pm, Sandy's classification was changed to post-tropical, a status
change made necessary because of structural changes within the system as it moved
north into a colder environment.
Heavy rain started Monday from the southeast to northwest as Sandy grazed Delaware and
approached the New Jersey shoreline. The heaviest rains were focused in South Jersey,
Eastern Maryland and Delaware where five to twelve inches of rain were reported. The
highest rainfall in the Mount Holly county warning area (CWA) was 12.49 inches in Easton, MD.
Several streams experienced crests above flood stage in these regions, in either the minor
or moderate flooding category. Areas further north received one to three inches of rain.
A flood watch was issued early Saturday morning and then expanded Saturday afternoon to cover
the entire NWS Mount Holly forecast area. This flood watch continued throughout the event.
Numerous flood warnings and statements were issued beginning early Monday morning and
continuing through Wednesday October 31.
Very high wind gusts were recorded due to Sandy, with the strongest winds north and east of
the center. Sandy provided some areas of the mid-Atlantic region with their highest wind
gusts since Hurricane Hazel 58 years earlier (October 1954), especially in New Jersey
and eastern Pennsylvania. Several wind gusts in Ocean County New Jersey were close to 90 mph,
with many regions reporting gusts over 50 mph. The highest wind gust reported
in the Mount Holly CWA was 89 mph in Surf city (Ocean County NJ) Winds gradually began to
increase Monday, peaking as the storm passed through the region Monday night. Many trees
and power lines were taken down as a result of these gusty winds.
A high wind watch was issued early Saturday morning along with a storm watch for coastal
waters and the Delaware Bay The high wind watch was upgraded to a high wind warning early
Sunday morning, while the storm watch for marine areas was upgraded to a storm warning
Saturday afternoon and then to a Hurricane Force Wind Warning around midday Sunday.
Sandy produced major to record storm surge along the entire New Jersey coast and in
Raritan bay. This was partially due to the timing of landfall which occurred near
the time of astronomical high tide along the New Jersey coast on Monday evening.
The forward speed of Sandy at the time of landfall, approximately 28 mph, also
helped push water ashore,especially from Atlantic City north, which was also in
the right-front quadrant of the storm. The previous record tide level at Sandy Hook,
set by Hurricane Donna in 1960, was shattered by 3.2 feet. As Sandy continued west
into Pennsylvania, a strong southeasterly flow on the backside of the storm,directed
up Delaware Bay, produced record water levels in the tidal sections of the Delaware
River at and near Philadelphia. Moderate flooding occurred on the Chesapeake Bay with no
major problems reported.
A coastal flood watch was issued early Saturday morning for the Atlantic coast and
Delaware Bay; this was upgraded to a warning Saturday afternoon. Coastal flood warnings
were issued for the tidal Delaware River early Sunday morning and for the eastern shore
of the upper Chesapeake Bay late Sunday afternoon.
Please browse to the following links for more information on Superstorm Sandy:
- Final assessment writeup
- Summary and Records set
- Briefings and Presentations
- Aerial survey photos of Sandy damage can be found here
- Additional Information on Superstorm Sandy
- NY Harbor Buoy Information from Superstorm Sandy
- Courtesy of USGS, coastal flooding survey of Sandy damage with areas flooded and
depths at specific points can be found at this link