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| A car goes through the high water as Hurricane Sandy bears down on the East Coast, Sunday, Oct. 28, 2012, in Ocean City, Md. Governors from North Carolina, where steady rains were whipped by gusting winds Saturday night, to Connecticut declared states of emergency. Delaware ordered mandatory evacuations for coastal communities by 8 p.m. Sunday. |
KENSINGTON, Md. (AP) -- The projected storm surge from Hurricane Sandy is a "worst case scenario" with devastating waves and tides predicted for the highly populated New York City metro area, government forecasters said Sunday.
The
more they observe it, the more the experts worry about the water -
which usually kills and does more damage than winds in hurricanes.
In
this case, seas will be amped up by giant waves and full-moon-powered
high tides. That will combine with drenching rains, triggering inland
flooding as the hurricane merges with a winter storm system that will
worsen it and hold it in place for days.
Louis
Uccellini, environmental prediction chief for the National Oceanic and
Atmospheric Administration, told The Associated Press that given Sandy's
due east-to-west track into New Jersey, that puts the worst of the
storm surge just north in New York City, Long Island and northern New
Jersey. "Yes, this is the worst case scenario," he said.
In
a measurement of pure kinetic energy, NOAA's hurricane research
division on Sunday ranked the surge and wave "destruction potential" for
Sandy - just the hurricane, not the hybrid storm it will eventually
become - at 5.8 on a 0 to 6 scale. The damage expected from winds will
be far less, experts said. Weather Underground meteorologist Jeff
Masters says that surge destruction potential number is a record and
it's due to the storm's massive size.
"You
have a lot of wind acting over a long distance of water for hundreds of
miles" and that piles the storm surge up when it finally comes ashore,
Masters said. Even though it doesn't pack much power in maximum wind
speed, the tremendous size of Sandy - more than 1,000 miles across with
tropical storm force winds - adds to the pummelling power when it comes
ashore, he said.
The storm surge energy
numbers are bigger than the deadly 2005 Hurricane Katrina, but that can
be misleading. Katrina's destruction was concentrated in a small area,
making it much worse, Masters said. Sandy's storm surge energy is spread
over a wider area. Also, Katrina hit a city that is below sea level and
had problems with levees.
National Hurricane
Center Director Rick Knabb said Hurricane Sandy's size means some
coastal parts of New York and New Jersey may see water rise from 6 to 11
feet from surge and waves. The rest of the coast north of Virginia can
expect 4 to 8 feet of surge.
The full moon Monday will add 2 to 3 inches to the storm surge in New York, Masters said.
"If
the forecasts hold true in terms of the amount of rainfall and the
amount of coastal flooding, that's going to be what drives up the losses
and that's what's going to hurt," said Susan Cutter, director of the
hazards and vulnerability research institute at the University of South
Carolina.
Cutter said she worries about coastal infrastructure, especially the New York subways, which were shutting down Sunday night.
Klaus
Jacob, a Columbia University researcher who has advised the city on
coastal risks, said, "We have to prepare to the extent we can, but I'm
afraid that from a subway point of view, I think it's beyond sheer
preparations. I do not think that there's enough emergency measures that
will help prevent the subway from flooding."
Knabb said millions of people may be harmed by inland flooding.
A
NOAA map of inland and coastal flood watches covers practically the
entire Northeast: all of Maryland, New Jersey, Delaware, and
Connecticut; most of Pennsylvania, New York, Massachusetts and Vermont,
and parts of northeastern Ohio, eastern Virginia, North Carolina, and
western New Hampshire.
Along the mid-Atlantic
coast, storm surge is already starting to build, Uccellini said. NOAA's
Coastal Services Center chief Margaret Davidson said to expect
"bodacious impacts" from both surge and inland flooding.
The surge - in which water steadily increases from the ocean- will be worst in the areas north of where Sandy comes ashore.
New
York will have the most intense storm surge if Sandy comes ashore
anywhere in New Jersey, Uccellini said. Only if it arrives farther
south, such as Delaware, will New York see a slightly, only slightly,
smaller storm surge.
In general, areas to the
south and west of landfall will get the heaviest of rains. Some areas of
Delaware and the Maryland and Virginia peninsula will see a foot of
rain over the several days the storm parks in the East, Uccellini said.
The rest of the mid-Atlantic region may see closer to 4 to 8 inches,
NOAA forecasts.
The good news about inland
flooding is that the rivers and ground aren't as saturated as they were
last year when Hurricane Irene struck, causing nearly $16 billion in
damage, much of it from inland flooding in places like Vermont,
Uccellini and Masters said.
The storm, which
threatens roughly 50 million in the eastern third of the country, began
as three systems. Two of those - an Arctic blast from the north and a
normal winter storm front with a low-pressure trough- have combined.
Hurricane Sandy will meld with those once it comes ashore, creating a
hybrid storm with some of the nastier characteristics of a hurricane and
a nor'easter, experts have said.
