Although Sandy, at its peak, was only a post-tropical cyclone when it hit the US, its winds spanned an area of 1,800 kilometers (1,100 miles), leading to extreme storm surges and waves that decimated the Jersey Shore, flattening communities and destroying the casinos and boardwalks on which the local economy largely depends. At Battery Park, on Manhattan’s south end, the surge height reached 4.2 meters, flooding homes and businesses and plunging millions into darkness.