EARTH: HURRICANES- SUBMERGED CITY
Howling winds rush between New York City's skyscrapers, shattering windows and uprooting trees. A 7.6
meter (25 foot) wall of water sweeps over Lower Manhattan, submerging the financial district and
popular neighborhoods like Chinatown and Little Italy (see map, right). Subways fill with seawater.
Millions of New Yorkers who evacuated the danger zone can't return to their devastated homes. [See
Sandy's Reality: 1]
Is this the script from a disaster movie? No, it's a scenario that experts warn could play out in real life.
Hurricanes have hit the Northeast barely missing the city in the past. And a 2001 report ranked New
York the third-most-vulnerable U.S. city to hurricanes, right behind New Orleans and Miami.
New Orleans found out the hard way what can happen when a major hurricane strikes a vulnerable city.
In 2005, Hurricane Katrina killed 1,800 people and filled New Orleans with floodwaters, forcing the city's
residents to flee their homes and take shelter in public arenas like the Astrodome in Houston, Texas.
With New York City's population at more than 8 million--16 times the population of New Orleans--could
such a tragedy multiply many times over? [See Sandy's Reality: 2]
FAST TRACK TO NEW YORK
The reason for concern isn't that the Big Apple is a hurricane hot spot. Atlantic hurricanes form far from
New York in the tropics, usually between the months of June and November. Warm water evaporating
from the ocean fuels their swirling, high-speed winds. As a hurricane rotates, slow-moving streams of air
called trade winds carry it across the ocean. Fortunately, most hurricanes run out of steam without
reaching land. Areas in the Caribbean, Gulf of Mexico, and Southeastern U.S. are at greatest risk for an
Atlantic hurricane hit, since the trade winds push storms in this direction.
The trade winds move at only 16 to 24 kilometers (10 to 15 miles) per hour, which gives people in the
storm's path time to prepare. But some storms turn north and are swept up by faster winds. Kerry
Emanuel, an atmospheric scientist at the Massachusetts Institute of Technology, explains, "If you get up
to [higher] latitudes, the winds tend to be much stronger. And so the hurricanes, when they get
embedded in those winds, move faster.” [See Sandy’s Reality: 3]
This means that a hurricane on track for New York could accelerate, forcing city residents to act fast.
“Accelerating hurricanes will cause watches and warnings to be issued more suddenly,” says Gary Conte,
warning coordination meteorologist for the National Weather Service’s Upton, New York, office. “So
people will certainly have less time to prepare for an approaching hurricane which is forecast to
accelerate here across the Northeast United States.” [See Sandy’s Reality: 4]
FUNNEL EFFECT
Usually, such a hurricane wouldn’t strike the city directly, because land to the south of New York acts as
a shield. Most strong storms pass to the east of the city. That’s what happened in 1938, when New
England’s worst recorded hurricane struck. Although the monster storm killed hundreds of people in
the Northeastern U.S., its strongest winds missed New York City.
But the city’s geographical location could also be its downfall. New York City sits on a bight, a curve in
the coastline that forms New York Bay. If a hurricane were to strike this spot, the storm surge (water
pushed toward shore by a hurricane) would funnel into the bay, piling up until it flooded parts of
Manhattan. Emanuel explains, “For the same storm hitting New York, at least at the right angle, you
could get a far bigger storm surge than that storm hitting a straight coastline, because the water has
nowhere to escape.” [See Sandy’s Reality: 5]
“That’s the nightmare scenario for New York,” says Greg Holland, an atmospheric scientist at the
National Center for Atmospheric Research. The nightmare has happened before. In 1821, a hurricane
swept into the bay. The trapped water rose into a 4 meter (13 foot) storm surge that put Lower
Manhattan underwater.
Back then, not many people lived in the flooded area. But today, this region is densely populated and
includes miles of subway tunnels. If a stronger hurricane were to strike this spot, Conte says, “You could
end up with sure values ranging from 20 to 25-plus feet across portions of New York City.” [See Sandy’s
Reality: 6]
This funnel effect is the reason the Big Apple ranks so high on the hurricane risk list. Holland says, “In
New York, the chances of getting [a hurricane] are actually fairly remote, but when you get one, if it’s
anything like the right track, then the consequences are going to be enormous.”
HURRICANE CYCLES
There is more bad news: Atlantic hurricanes appear to run in cycles. In the mid-1990’s, a new cycle
started in which both the number and intensity of hurricanes have increased. Holland says, “It’s the
classic double whammy.” [See Sandy’s Reality: 7]
Normally, scientists would expect the cycle to run its course and the number of hurricanes to decrease.
But climate change could throw a wrench in the cycle as rising sea surface temperatures and shifting
wind patterns affect hurricane formation and tracks. “Climate change is expected to affect hurricane
activity in ways that we’re still struggling to grasp,” Emanuel says. Some studies predict that the number
of hurricanes will drop but that the storms will become more intense.
The chance of the nightmare storm hitting the Big Apple may be small, but city officials are taking it
seriously. Even though New Yorkers need not live in fear, experts urge them to have a disaster plan.
After all, says Holland, “it gets pretty hard to think logically once the winds start howling and the water
starts running around your ankles. A little forethought can make a big difference in an emergency. –
Jacqueline Adams