You can see La Nina years when the Atlantic is warm produced 15 landfalling east coast storms in 9 years, 11 were major hurricanes, 9 affecting the northeast directly on second or third landfall. We discussed the 1938 direct hit hurricane in a recent story here.
Christopher Landsea (HRD) and Roger Pielke Jr. estimated if a storm like the Hurricane of '38 were to happen today, it would be the sixth costliest of all-time.
FAR WORSE IF TRACKS FURTHER WEST TO NEW YORK CITY
Experts earlier this decade had proclaimed after Miami and New Orleans, New York City was considered the third most vulnerable major city for the next hurricane disaster.
AIR Worldwide’s Karen Clark at the National Catastrophe Insurance Program Summit in November, 2005 said if such a storm made landfall just to the east of New York City, it would result in approximately $50 billion of insured losses with total economic losses exceeding $100 billion…. "since the total value of exposed properties in coastal areas of New York State alone has increased to over $1.9 trillion.“
A major hurricane making a major hit would be the costliest storm of all time, eclipsing Katrina.
Approximately one-quarter of the $100 billion in total economic losses would be attributable to storm surge. The contour of New York's coastline and relatively shallow depth of its coastal waters make it extremely vulnerable to storm surge.
At the time of the 1938 storm, Long Island was a rural home for oyster fishermen, potato farmers and wealthy industrialists. More than 20 million people live in the greater metropolitan region today. Many live on coastal land, reclaimed swamp and barrier islands. Much of Lower Manhattan is built on landfill. Places like Rockaway, Coney Island and Manhattan Beach "are stretches of land that nature has created to protect the mainland from hurricanes," Mike Lee (NYCOEM) says. "In our civilization this is also the most desirable land to develop and build on. ... so we now have to deal with the threat."
A storm surge prediction program used by forecasters called SLOSH (Sea, Lake, and Overland Surge from Hurricanes) has predicted that in a category 4 hurricane, John F. Kennedy International Airport would be under 20 feet of water and sea water would pour through the Holland and Brooklyn-Battery tunnels and into the city's subways throughout lower Manhattan.
The highest storm surges (Category 4) would occur in the following regions:
• Amityville Harbor - 29 feet
• Atlantic Beach & Long Beach areas - 24 to 28 feet
• South Oyster Bay, Middle Bay, & East Bay areas - 24 to 28 feet
Army Corp Models show even worse impacts. In the event of a direct hit by a category-3+ hurricane, surge maps show that the Holland and Battery Tunnels will be completely filled with sea water, with many subway and railroad tunnels severely flooded as well. The runways of LaGuardia and JFK airports will get flooded by 18.1 and 31.2 feet of water, respectively. If a storm like the Long Island Express makes a direct hit on the city, everything below Broome Street will be inundated, some parts under as much as 20 and 30 feet of water. Chelsea and Greenwich Village would be completely flooded, with the Hudson spilling over all the way to 7th Avenue. Likewise, the East River and East Village become one, with ocean water surging all the way to 1st Avenue.
If you haven't evacuated before the storm, forget it. During the storm, Manhattan's east- and west-side highways vanish. Tunnels and bridges become unusable.
Today, approximately 78.5% of current New York State coastal residents have never experienced a major hurricane (Hughes). Though New Yorkers are aware what hurricanes can do (images of Katrina have been burned in their memory), there is a misguided sense that this region is not vulnerable to same kind of storm as the Gulf or Florida and would experience only minor inconveniences (downed trees, flooded basements and temporary power outages). In reality even here in the northeast, strong hurricanes threaten to bring a wall of water two stories high, winds on a large-scale the equivalent of an F2 or even F3 tornado, and a normal season's rainfall in a day.
Scott A. Mandia, Professor of Physical Sciences, SUNY Suffolk has put together an excellent page showing Long Island storm surge maps and animations here for various category hurricanes. From that site, the following
Hurricane storm surge causes approximately 90% of all storm deaths and injuries and much of the damage, therefore it is important for residents of Long Island, New York to be aware of the areas that will be affected by the storm surge. The southern shore of Long Island is most vulnerable to storm surge inundation because hurricane landfall will first occur there and the low elevation will allow sea water to move well inland.
The height of maximum storm surge is a function of storm strength, location of eye landfall, tidal time of landfall, elevation, and speed of storm. The images below represent the various regions of the southern shores of Long Island as well as the north and south forks as they would be affected by storm surge from various strength hurricanes. The images are derived from HURREVAC, a DOS-based software application that uses historical storm data and Long Island regional topography to estimate areas that would be inundated by water. (It should be noted that category 5 storm surges are not predicted by HURREVAC since there is little probability of such storms and no historical data exists for reference.) Each zone assumes landfall within that zone at normal tidal height. For high tide landfall, one would need to add 1/2 normal tide height to the predicted surge, while landfall at low tide would require a subtraction of 1/2 normal tide height from the predicted surge. The animated image was created using Microsoft GIF Animator and shows a loop of all maps within the zone with a five second interval between images.
The key appearing above indicates maximum storm surge height in that region for each category strength. For this example, the storm surge height for a category 4 hurricane would be 29 feet above normal sea-level.