Greetings Podger:
Since you did not specify whether or not you wanted a land or sea
storm, I have chosen to go with an "extreme hurricane" or
"extratropical" storm scenario because of the location of Manhattan in
relation to the Atlantic seaboard. I'm going to list the effects on
NYC first and then show an example of how the storm could build to
affect Manhattan.
The way I went about collecting the information was to begin at the
Goddard Institute for Space Studies at
http://www.giss.nasa.gov/data/stormtracks/ where I found the Atlas of
Extratropical Storm Tracks. FOTRAN data and maps are available there
for all storms from 1961 to 1999. I began viewing the maps and
looking at the storm tracks and saw heavy readings in the NY seaboard
area and it is definitely possible for a cateory 5 (or larger??) to
seriously affect NYC.
From another link, I found a phone number for the National Severe
Storms Laboratory and I called and spoke to a lady named Kelly who
suggested I phone a gentleman named Frank Lepore at the Hurricane
Prediction Center. Mr. Lepore was of immense assistance and you may
want to consider crediting him as a source in your book.
Lepore educated me regarding the consequences of a severe hurricane on
New York City:
* If a hurricane is on a NW track, it is strongest in the NE quadrant
as it approaches land. For instance, if the track is towards southern
NY near the Delmarva peninsula
(http://www.sandseekers.net/html/del_pen_map.htm or
http://home.dmv.com/~les/DELMARVA.HTM), a strong NE side would occur
where NJ meets Long island.
* The major effects of the wind on the surface of the water coupled
with falling barometric pressure would lift the water and could
conceivably cause a build-up of 17 to 20 feet of water being pushed
into the Hudson river. This would cause major tunnel flooding in the
city and, while it would probably not bring any buildings down, it has
the potential to disrupt all electrical service causing a city-wide
blackout because of the interconnecting electrical circuits throughout
the city. People in tunnels (subway, Holland, etc) when it happened
would be in grave peril. This, coupled with the rains, could be the
most effective street sweeping that NYC has ever had...
* Few high rise building windows in Manhattan are rated for a category
5 hurricane so the wind load on the glass would send it shattering
inward and cascading down to the streets. As the wind became more and
more compressed moving through the buildings, the channelization would
increase the wind velocity. This is known as the Venturi effect
("Bernoulli's theorem -sometimes called the Venturi effect- implies
that a decrease in fluid pressure is associated with an increase in
the fluid's velocity/speed. It's the basics for aircraft wing design
explaining that air flowing over the upper, curved part of the wing
moves faster than the air on the underside of the wing so that the
pressure underneath is greater and hence causes lift." - see
http://www.spartechsoftware.com/reeko/Glossary.htm). As the wind is
compressed faster and faster, the windows would be compromised and the
wind swirling inside the buildings would be, as Lepore put it, "like a
MixMaster." Lepore said that hallways should be safe because of few
or no windows. Also, the wind increases at higher elevations, too, so
marry that to the Venturi effect and the topmost residents of NYC
would be in the most dangerous situation.
* Tornadoes can also be generated by the hurricane winds as another
byproduct of the storm. Imagine a series of tornadoes barrelling down
the Fifth Avenue and and taking the contents of Tiffany's or Stuben's
with it. The occupants of subway cars travelling on elevated tracks
would also be in grave peril.
* Other occurrences might include broken water mains, parts of
buildings' architecture being dislodged and falling to the street to
kill or maim pedestrians, extreme looting, etc.
*******
Lepore also pointed me towards research done by Nicholas Coch who is a
Professor of Geology at Queens College. He has studied extensively
the great hurricane of 1938 and has written much about it. I located
Mr. Coch's public number at Queens College and phoned him. I got his
machine and left a message for him to call. I am hoping he may be
able to point me to his research online and I will let you know if he
returns my call and the information he provides. He was referred to
in one article as the "father of hurricane forensics."
At http://info.insure.com/home/disaster/1938hurricane.html in an
article about Coch's research, it is stated "Researchers say a replay
of the 1938 hurricane would be especially devastating because of the
monstrous storm surge and heavy flooding associated with the storm.
Seas in Rhode Island during the height of the storm rose to 17 feet
above normal high tide. Heavy rains before and during the storm
produced river flooding, especially along the Connecticut River near
Springfield, Mass. Koch says a similar storm could possibly bury New
York's JFK airport under 20 feet of water." The 1938 hurricane was
considered a category 3 - Hurricane Andrew was a category 5.
The article also states "A major hurricane striking the heavily
populated regions of the Northeast is the least anticipated — and
least prepared for — hurricane scenario today, according to AIR
Worldwide Corp. (AIR), a catastrophe-modeling and weather-risk
management company. This is because the region is often given less
attention when assessing exposure to hurricane risk due to the
relative infrequency of such an event. Statistically speaking,
hurricanes of this severity occur once every 125 years on average."
*******
I downloaded the file of the Hurricane Inundation Zones of
Westchester, Suffolk, Nassau Counties, and New York City, New York
provided by the New York State Emergency Management Office (SEMO).
The download link for the zip file is located at
http://www.nysgis.state.ny.us/gis9/slosh.zip but I couldn't get it to
open. I was hoping there was an NYC model among the files. Perhaps
you'll have better luck with opening it. Mr. Lepore also suggested
this source and I located the file at
http://www.nysgis.state.ny.us/gis3/data/semo.NYSLOSH.html#Identification_Information.
Also see Long Island Inundation Mapping at
http://www.nan.usace.army.mil/business/prjlinks/coastal/longbeac/graphics/lbmap.jpg
for areas affected (category 1 and 2 hurricane only so imagine a
category 5+ and you have a real mess) and please review the US Army
Corps of Engineers New York State fact sheet "Atlantic Coast of New
York, Jones Inlet to East Rockaway Inlet, Long Beach Island, New York
Storm Damage Reduction Project " at
http://www.nan.usace.army.mil/project/newyork/factsh/pdf/lbeach.pdf
Storm Surge Simulation for Long Island - water levels for categories
2, 3 and 4 simulated in photographs
http://www.nhc.noaa.gov/HAW/day1/long_island.htm
See also the SLOSH (Sea, Lake and Overland Surges from Hurricanes)
animation model for storm surge on the Gulf Coast at
http://www.nhc.noaa.gov/HAW/day1/images/slosh2.gif - the SLOSH model
explained by FEMA is located at
http://www.fema.gov/hazards/hurricanes/sloshmodel.shtm
*******
As for how and where the storm would begin, the model for the 1938
huricane of New England at
http://www.nhc.noaa.gov/HAW/basics/historic_storms.htm#new could be
used:
"The "Long Island Express' was first detected over the tropical
Atlantic on September 13, although it may have formed a few days
earlier. Moving generally west-northwestward, it passed to the north
of Puerto Rico on the 18th and 19th, likely as a category 5 hurricane.
It turned northward on September 20 and by the morning of the 21st it
was 100 to 150 miles east of Cape Hatteras, NC. At that point, the
hurricane accelerated to a forward motion of 60 to 70 mph, making
landfall over Long Island and Connecticut that afternoon as a Category
3 hurricane. The storm became extratropical after landfall and
dissipated over southeastern Canada on September 22.
"Blue Hill Observatory, MA measured sustained winds of 121 mph with
gusts to 183 mph (likely influenced by terrain). A U.S. Coast Guard
station on Long Island measured a minimum pressure of 27.94 in. Storm
surges of 10 to 12 ft inundated portions of the coast from Long Island
and Connecticut eastward to southeastern Massachusetts, with the most
notable surges in Narragansett Bay and Buzzards Bay. Heavy rains
before and during the hurricane produced river flooding, most notably
along the Connecticut River.
This hurricane struck with little warning and was responsible for 600
deaths and $308 million in damage in the United States."
At the same URL, you will find other tracks of historic hurricanes,
some that were on the Atlantic coast, at
http://www.nhc.noaa.gov/HAW/basics/historic_storms.htm#top - Hurricane
Hazel is described there and it was an October hurricane. See
http://www.nhc.noaa.gov/HAW/basics/historic_storms.htm#hazel for
another possible track journal.
*******
Should you require clarification of any of the links or information I
have provided, please request it and I will be happy to respond. You
have enabled me to have a most interesting day of research!
SEARCH STRATEGY:
severe storm research
U.S. jet stream map
atlantic ocean jet stream map
storm inundation map NY
"Venturi effect" definition
Delmarva peninsula map
Nicolas Coch hurricane
Nicolas Kock hurricane
slosh model |
