Hurricane Sandy was a late-season tropical cyclone that brought catastrophic effects to portions of the Caribbean, Mid-Atlantic and Northeastern United States. Sandy was the largest Atlantic hurricane in diameter on record; its winds stretched approximately 1,100 miles from end to end. The eighteenth tropical cyclone and named storm and tenth hurricane of the 2012 Atlantic hurricane season, Sandy developed from a tropical wave in the western Caribbean Sea on October 21. It became a tropical depression, quickly strengthened, and was upgraded to a tropical storm six hours later. Sandy moved slowly northward toward the Greater Antilles and gradually intensified.
On October 24, Sandy was upgraded to a hurricane, shortly before making landfall in Jamaica. Upon moving farther north, Sandy re-entered water and made its second landfall in Cuba during the early morning of October 25 as a Category 2 hurricane. During the late evening of October 25, Sandy weakened to Category 1 strength; in the early hours of October 26, it headed north through the Bahamas. Sandy briefly weakened to a tropical storm in the early morning hours of October 27, then restrengthened to a Category 1 hurricane later that morning. Just before 8 a.m. EDT on October 29, Sandy turned to the north-northwest and started to make its expected approach towards the U.S. coast, still maintaining Category 1 strength. The National Hurricane Center (NHC) announced that the storm had come ashore about 8 p.m. EDT 5 miles southwest of Atlantic City, New Jersey. On October 29, 2012, at 7 p.m. EDT, Sandy was declared a post-tropical cyclone.
Sandy's impact on the United States affected at least 22 states, stretching from Florida to New England with tropical storm force winds stretching far inland and mountain snows in West Virginia. The cyclone brought a storm surge to New York City on the evening of October 29, with numerous streets and tunnels flooded in Lower Manhattan and other areas of the city.