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Posted at 11:10 AM ET, 10/31/2012

From the devastating surge to crippling snow, Hurricane Sandy by the numbers


Floodwaters surround homes near the Mantoloking Bridge the morning after hybrid storm Sandy rolled through, Tuesday, Oct. 30, 2012, in Mantoloking, N.J. Sandy, which was downgraded from a Hurricane just before making landfall in New Jersey, left millions without power. (Julio Cortez/AP)
Superstorm Sandy slowly weakened over land Tuesday, but not before leaving behind a massive trail of destruction across the Northeast and Mid-Atlantic. Initial estimates suggest the powerful storm has claimed at least 51 lives and caused up to $20 billion in damage.

With adverse effects from the central Appalachians well into New England, Sandy will long be remembered for the unusual mix of weather conditions it brought millions of people across the Eastern Seaboard.

As the numbers continue to come in, let’s take a look at some of Sandy’s most impressive weather data:

Storm pressure

With a minimum central pressure of 940 mb while churning off the New Jersey coast, Sandy was one of the strongest storms to strike the Northeastern U.S. in decades. As it made landfall just south of Atlantic City, N.J., Sandy had begun transitioning to a post-tropical storm. At that time its central pressure measured 946 mb, making it the second-lowest pressure of any storm to make landfall north of Cape Hatteras, N.C. For historical comparison, only the Long Island Express Hurricane of 1938 had a lower pressure reading (941 mb) at landfall. As a rule of thumb, the lower the pressure, the more intense the storm.

Areas under Sandy’s impact zone also recorded historically low pressures. Consider these all-time record low pressure readings (from Wunderground’s Jeff Masters):

- 948 mb in Atlantic City, N.J. (old record: 961 mb on 3/6/1932)
- 953 mb in Philadelphia, Pa. (old record: 963 mb on 3/13/1993)
- 958 mb in Trenton, N.J. (old record: 963 mb on 3/13/1993)
- 964.4 mb in Baltimore, Md. (old record: 965.9 mb on 3/13/1993)

Hagerstown, Md. also recorded a record low pressure of 969 mb, just below the prior record of 970 mb set during the March 13, 1993 superstorm.

Winds


NOAA’s GOES-13 satellite captured this visible image of Hurricane Sandy battering the U.S. East coast on Monday, Oct. 29 at 9:10 a.m. EDT. (NASA)
Sandy’s violent winds were felt far and wide from the Atlantic coast well into the interior Northeast. The storm’s sustained winds peaked at 90 mph at 11 a.m. on Oct. 29, as Sandy strengthened over the warm waters of the Gulf Stream. At landfall, sustained winds were a slightly lower 80 mph – but still well within Category 1 hurricane strength.

Sandy’s wind field was already impressive days before it pummeled the coast. More than 24 hours prior to landfall, winds extended some 520 miles from the storm’s center of circulation. As Sandy came ashore in New Jersey, several locations along the East Coast recorded hurricane-force wind gusts. Here’s a summary of data reported (h/t: AccuWeather and SI Weather):

New York

-96 mph: Eaton’s Park
-90 mph: Islip
-79 mph: JFK Int’l Airport
-74 mph: LaGuardia Airport
-62 mph: Central Park

New Jersey, Pennsylvania

-89 mph: Surf City, N.J.
-88 mph: Montclair, N.J.
-78 mph: Newark Int’l Airport, N.J.
-81 mph: Allentown, Pa.
-68 mph: Philadelphia Int’l Airport

In the greater Washington, D.C. area, Sandy brought slightly lower wind gusts generally, but isolated gusts topped 80 mph, including a 90 mph gust at the Chesapeake Bay Bridge. Some other notable gusts:

-79 mph: Thomas Point, Md.
-79 mph: Chester Gap, Va.
-76 mph: Laytonsville, Md.
-61 mph: Reagan National Airport
-60 mph: Baltimore-Washington (BWI) Airport

Rain


Rainfall totals from Superstorm Sandy through October 30. Darker areas indicate the highest precipitation amounts. (NOAA)
In addition to damaging winds, Sandy broke multiple daily rainfall records, including new records at all three D.C. area airports. While Sandy’s most devastating impacts were in New Jersey and New York City, the storm’s heaviest rainfall occurred on its southwestern flank. The result was copious rain from southeastern Virginia up through eastern Maryland and the Delmarva peninsula. In some places, Sandy dumped more than 8 inches of rain as its winds pelted the coast.

CapitalClimate summarizes several new precipitation records for October 29 across the mid-Atlantic and Northeast (old records in parentheses):

-3.85” in Washington D.C., at Reagan National Airport (2.69” in 1885)

-2.68” in Philadelphia (1.72” in 1953)

-4.79” in Atlantic City, N.J. (2.33” in 1908)

-3.79” in Wilmington, Del. (2.56” in 1953)

The NWS also reported that Oct. 29 set new records for the wettest October calendar day at both Washington-Dulles and BWI International Airports. At Dulles, 4.25” of rain fell, breaking the previous record-wettest October calendar day of 4.06” from Oct. 1, 1979. At BWI, 5.51” of rainfall on Monday broke Baltimore’s earlier record-wettest October calendar day of 4.38” from Oct. 10, 1922.

AccuWeather has an excellent list of the highest rainfall totals recorded in states affected by Sandy. Not far from D.C., Easton, Md. recorded 12.55”, which puts it near the top of the list.

Snow

Sandy’s unusual development as a tropical system merging with a winter cold front brought high elevations very heavy snowfall – rare even for this time of year. Redhouse, Md. (Garrett County) measured an impressive 28 inches, topping the list for greatest accumulation among the eight states that saw measurable snowfall. Unofficial observations suggest even higher amounts, including more than 28” in Davis, W.Va. In some places, it’s still snowing.


Snowfall analysis indicate a large area of 20-30 inch snowfall in eastern West Virginia, and 30 to 40 inches in a few areas. (National Weather Service)
Charleston, W. Va. has recorded 10.1” so far, enough to make this October its snowiest on record. Charleston, Elkins and Bluefield all had their snowiest October day Monday, receiving 9.4”, 7”, and 4.7” respectively (source: the Weather Channel).

Sandy’s snow output covered an enormous area. All told, the storm dumped more than a foot of snow in Virginia, West Virginia, Pennsylvania, North Carolina, Tennessee, and Kentucky. Perhaps most unusual were the snow accumulations in the south-central Appalachians, including an incredible 22” in Newfound Gap stradling the line between North Carolina and Tennessee.

Storm surge

Of course, Sandy’s greatest impact was the combination of high wind and rain that brought destructive storm surges and flooding to many coastal areas. Storm surges were enhanced by a full moon, which allowed water levels to crest several feet above normal tides. Major storm surge damage stretched from Chincoteague, Va. through Atlantic City, New Jersey to Rhode Island.

New York City was especially hard hit as Sandy’s onshore (northeasterly) winds drove water into Brooklyn and lower Manhattan. The New York Times reported of seawater flooding seven subway tunnels under the East River and of submerged runways at both JFK and LaGuardia airports.


Water levels at the Battery in New York City. On Monday night, the storm tide (combination of surge and high tide) reached 13.88 feet above normal, a record. (NOAA)
Here are some of Sandy’s most significant storm surges – measured as feet above normal average low tide:

-14.38 ft at Kings Point, N.Y.

-13.88 ft at The Battery, Lower Manhattan

-13.31 ft at Sandy Hook, N.J.

The 13.88 ft water level at the Battery surpassed the old record of 10.02 ft measured there during Hurricane Donna in 1960 and also eclipsed an estimated 11.2 ft water level seen during a hurricane in 1821.

From storm surges to flooding rains and destructive winds, Superstorm Sandy has left its meteorological mark as the Northeast begins to recover from its destructive force.

Related:

Maps of flooding and subway outages in New York (NY Times)

Did climate change contribute to Hurricane Sandy’s devastation? (NY Times blog)

Photo Galleries:

Sandy’s devastating blow

Sandy swamps New York area

The Big Picture blog

By  |  11:10 AM ET, 10/31/2012

Categories:  Latest, Tropical Weather, Winter Storms

 
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