I have been through a number of cyclones at least as large, & much stronger than Sandy, in our tropical east coast area. During much of this time my home was not much more than 30Cm above the spring high tide line.

I have often wondered, rather idly, why the US east coast has such high cyclone surges. I have assumed it is to do with their gently shelving continental shelf, & the topography of coastal districts, but never known.

We are lucky in that our lack of Gulf Stream heating of our non tropical waters saves us from these things in the latitudes that the US experiences them. Still even where we are prone to them we don't get such huge surges.

I have wondered if the Barrier reef helps protect us there.

So there it is folks, my ignorance laid bare, & my laziness too I guess, asking you to hand me the information I am too lazy to research. It was a photo of water gushing into an underground station, & & another of the depth of water in New York that triggered my interest, so I thought of all the expertise on here going to waste.

Good topic, Hasbeen.

Here's a little something to chew on:

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

I presume much of the coast affected by Sandy is low-lying and gently sloping. I heard someone refer to some of the flooded area around New York as being "reclaimed"

Population, building and Infrastructure Density, the answer in a line.
Then Poirots truth about the location, add the circumstances, the clash of weather pattens.
If a tree falls in the forest, and no one is there, will it still make a noise?
We can be happy past storms did not kill thousands, who did not live in its path.

@ Poirot,

New York (Manhattan and surrounds) is the most heavily populated low-lying area in America. Central Park is built on swampland and much of the shore line of Manhattan, with its cycle ways, paths and parks, is ‘reclaimed’.

@ Hasbeen

I don’t really understand the title of this thread. Are you asking why a Category 1 Hurricane, usual in August but rare in late October, sent inland by a polar front from the northeast rather than being able to continue its normal northward journey offshore, as well as coinciding with a lunar full tide, should cause so much damage to the densely populated and low-lying northeast US coastline? If so, I would have thought the answer was obvious.

Apart from the seaside cities and towns that line the shore, from the Carolinas all the way to Boston, many of which are merely a metre or so above sea level, Manhattan, the Bronx, Queens and Staten Island are low lying areas surrounded by water, namely the Hudson and East rivers. When the storm surges caused by Sandy (regardless of its category or wind speed) flowed north up the Hudson and East rivers as well as south, the waters 'met in the middle' and swelled further. That water had to go somewhere – in this case across the land, much of which by now was below sea level due to the storm surges and the high tide. This water, driven by wind gusts of up to 85mph, wreaked havoc.

Sandy was not “downgraded” when it reached land, as some have claimed. It was instead categorized as a “post-tropical storm”, not because its intensity lessened, but because, under the influence of the freezing northeasterly pushing it inland, it was cold. The nature of Sandy has been commented on by many on-scene reporters and residents as being unusual because a) the wind gusted, rather than blew constantly, b) the weather was cold, with bands of sleet and ice accompanying rain, c) the sheer size (measuring up to 400 miles across).

Given that, it is easy to see why Sandy caused so much damage.

Excellent summary, scribbler.

Thanks for clarifying a few points in such a succinct manner.

The title is confusing, mainly i think someone was trying to get in before it was blamed on climate change.
Best to say ocean temperatures don't exist and nothing has changed.