Depending On Tides, The Storm Surge Could Be Bad News For Manhattan (It's An Island)

[KittyWampus]

Irene’s storm surge may flood New York City’s subway system

The floodwalls protecting Manhattan are only five feet above mean sea level. During the December 12, 1992 Nor’easter, powerful winds from the 990 mb storm drove an 8-foot storm surge into the Battery Park on the south end of Manhattan. The ocean poured over the city’s seawall for several hours, flooding the NYC subway and the Port Authority Trans-Hudson Corporation (PATH) train systems in Hoboken New Jersey.

FDR Drive in lower Manhattan was flooded with 4 feet of water, which stranded more than 50 cars and required scuba divers to rescue some of the drivers.

Mass transit between New Jersey and New York was down for ten days, and the storm did hundreds of millions in damage to the city.

Tropical Storm Floyd of 1999 generated a storm surge just over 3 feet at the Battery, but the surge came at low tide, and did not flood Manhattan.

The highest water level recorded at the Battery in the past century came in September 1960 during Hurricane Donna, which brought a storm surge of 8.36 feet to the Battery and flooded lower Manhattan to West and Cortland Streets.

However, the highest storm surge on record in New York City occurred during the September 3, 1821 hurricane, the only hurricane ever to make a direct hit on the city. The water rose 13 feet in just one hour at the Battery, and flooded lower Manhattan as far north as Canal Street, an area that now has the nation’s financial center. The total surge is unknown from this greatest New York City hurricane, which was probably a Category 2 storm with 110 mph winds.

[eleny]

1. Link to pdf of the map showing vulnerability of NYC neighborhoods for various hurricane strengths

http://www.nyc.gov/html/oem/downloads/pdf/hurricane_map_english.pdf

P.S. I think that I heard on tv that the tides were going to be high.

[FedUpWithIt All]

2. I just read this...

Hurricane Irene: Top five hurricanes to hit the US
As Hurricane Irene threatens to become the biggest storm to hit America in seven years, the top five deadliest and the top five costliest hurricanes to strike the US:

:scared:

http://www.telegraph.co.uk/news/worldnews/northamerica/usa/8722957/Hurricane-Irene-Top-five-hurricanes-to-hit-the-US.html

[nadinbrzezinski]

3. Why do I need to rely on british press for the really bad nooz?

I know... I know....

For the record here hoping it peters out...

[Lucinda]

4. I read earlier that they were expecting high tides when the storm is due

So much will depend on what happens the next day or so. :(

[highplainsdem]

5. The highest tide of the entire month, according to what I heard. Very bad combined with the surge.

[BeFree]

7. Hudson river

How is it flowing? USGS could tell ya at what stage it is. If it is flowing near a high and it gets backed up at the mouth, then it will back up and flood.

I imagine the Hudson is near peak, with all the rain upstate.

[kentauros]

12. Here ya go: Advanced Hydrological Prediction Service (NWS)

http://water.weather.gov/ahps2/index.php?wfo=okx

Click on the little green squares and circles to go to the data-page for that water source.

It's a pretty cool service. I use it in Houston during flood-stage in the bayous :)

[FedUpWithIt All]

9. From National Geographic...

Meteorologist Jeff Masters, director of the Weather Underground website, said flooding caused by Hurricane Irene could be worse than usual, because the storm will be making landfall during a new moon.

During new and full moons, the sun, Earth, and the moon are arranged in a straight line, with the sun and moon intensifying each other's gravitational pull on Earth. The result is more severe tidal fluctuations—low tides are lower than usual, but more to the point, high tides are higher.

Due to these so-called spring tides ("spring" in the sense of jumping), any town that sees the hurricane pass by during one of the two daily high tides is especially in danger of heavy flooding due to storm surges—for example, if Atlantic City, New Jersey, is hit between 7 and 8 p.m. ET Sunday, Masters said.

Storm surges are caused by a hurricane's high winds, which pile up a "mound" of water along the front of the eye as the storm moves forward. A Category 3 hurricane can push a storm surge of 9 to 12 feet (2.7 to 3.7 meters) tall ashore at landfall.

In general, Masters is especially worried about coastal New Jersey, where Hurricane Irene's storm surge could exceed ten feet (three meters). It's not so much the surge height that concerns him as the state's lack of hurricane experience.


http://news.nationalgeographic.com/news/2011/08/110825-hurricane-irene-outer-banks-storm-tracker-weather-nation-major-path/

[elleng]

6. Ironic, eh?

'flooded lower Manhattan as far north as Canal Street, an area that now has the nation’s financial center.'

We the People can't do it, but Nature can!

[Stinky The Clown]

8. Geography also conspires against Manhattan Island

Long Island forms a right angle with New Jersey. New York Harbor (the mouth of the Hudson River) is right in the corner. As a hurricane approaches, it pushes storm surge ahead and to the left. That makes the water pile up at that right angle corner. With no place to go, it builds higher than it might otherwise.

Donna did this in the late 50s (maybe 1960? 61?).

[elleng]

11. Donna, 1960.

Donna was the only hurricane to affect every state along the East Coast with hurricane-force winds.

http://en.wikipedia.org/wiki/Hurricane_Donna

Got out of high school for Donna. (Long Island)

[gristy]

10. difference between high and low tide at GW bridge is about 5 feet

So a surge of anything over 2 1/2' takes the ocean up over the wall if it happens at high tide.

[krispos42]

13. Quick! Sell it back to the Dutch.

And nobody say ANYTHING about the hurricane until after the money transfer!