The Timeline and Impact of Hurricane Sandy

Hurricane Sandy, also known as “Superstorm Sandy,” was the most intense storm of the 2012 Atlantic hurricane season. As of the publication date of this article, it is ranked as the largest (by the span of its tropical-storm-force winds) and fifth-most expensive Atlantic hurricane on record.

Between Oct. 22-29, the late-season storm ravaged the Caribbean and 24 states across the eastern seaboard of the United States. Even after weakening to a post-tropical cyclone on Oct. 29, Sandy continued exhibiting hurricane-force winds while impacting the northeastern United States and eastern Canada — an occurrence which ultimately led the National Oceanic and Atmospheric Administration's (NOAA's) National Hurricane Center (NHC) and National Weather Service (NWS) agencies to change how they issue tropical cyclone watches and warnings.

At its strongest, Sandy was a Category 3 major hurricane with peak winds of 115 mph. At its largest, it measured over 1,000 miles in diameter, or roughly one-fifth the size of the United States.

Hurricane Sandy Timeline

Oct. 22-23

The disturbance that would eventually spin up into Sandy first appeared off the west coast of Africa around Oct. 11, and by Oct. 22, formed into a tropical depression in the southwestern Caribbean Sea. Six hours later, the low pressure strengthened into tropical storm Sandy.

Oct. 24-26

On the morning of Oct. 24, Sandy strengthened into a Category 1 hurricane with maximum sustained winds of 80 mph while positioned roughly 80 miles south of Kingston, Jamaica. It made landfall near Kingston that afternoon. By that evening, Sandy moved back over open waters and intensified into a Category 3 major hurricane. Shortly after midnight on Oct. 25, Sandy made landfall near Cuba's second-largest city, Santiago de Cuba, with maximum sustained winds of 110 mph.

Oct. 27-29

Sandy regained Category 1 hurricane strength around daybreak on Oct. 27 near the northern Bahamas. For the next two days, Sandy tracked northeastward over the open waters of the North Atlantic, parallel to the U.S. coastline. Midday on Oct. 29, the storm strengthened slightly and reached a second peak intensity of 90 mph, and by that afternoon, veered northwestward aiming for the state of New Jersey. While following this path, Sandy tracked over much cooler waters and also merged with a nor’easter, and by sundown on Oct. 29, had weakened to a post-tropical cyclone before making landfall near Atlantic City, New Jersey an hour or so later. However, despite being post-tropical, Sandy still exhibited hurricane-force winds and a minimum central pressure of 946 mb.

Oct. 30-Nov. 2

As a result of being downgraded to post-tropical, the NHC stopped issuing advisories for Sandy on Oct. 30. At the time of landfall, Sandy’s central pressure was 946 mb, which is the lowest pressure of any tropical cyclone that far north (it ties with the 1938 Long Island Express Hurricane). Meanwhile, Post-Tropical Cyclone Sandy continued moving westward across southern New Jersey, northern Delaware, and southern Pennsylvania. By Halloween, the storm's center had moved over northeastern Ohio. (Its end-of-October occurrence earned it the nickname “Frankenstorm” Sandy.)

Sandy also began impacting eastern Canada on Oct. 30. Its high winds, which reached nearly 50 mph and gusted up to 65 mph, triggered thousands of power outages throughout Ontario and Quebec. On Oct. 31, Sandy even spawned a weak tornado in Mont Laurier, Quebec. In all, Canada experienced over $100 million in damages.

By the first few days of November, Sandy's remnants had merged with a low-pressure system over eastern Canada.

The Aftermath of Sandy

Sandy dumped its heaviest rains across parts of Jamaica, including over 28 inches reported in Mill Bank, Jamaica. It was also one of the costliest hurricanes in the history of Cuba, with the storm damage and restrictions to food or water affecting 1.3 million people.

However, it was the U.S. states of New Jersey and New York that were among the hardest hit, despite the fact that Sandy was no longer a tropical cyclone when it hit New England. As a result of its monstrous size, Sandy drove catastrophic storm surges of over 12 feet into the New York coastline. In New Jersey, the storm's wind-driven waves inundated the Jersey Shore, destroying the Casino Pier amusement park in Seaside Heights (which partially reopened in 2013 and then was expanded in 2017) as well as a devastating number of houses, businesses, and community spots along the shore. Sandy even led the New York Stock Exchange to close for two days — something that hadn't happened since 1888.

When all was said and done, Sandy caused a total of nearly $78 billion in damages and 159 fatalities. As a result, the World Meteorological Organization retired the name “Sandy,” barring its use for any future tropical storms or hurricanes in the Atlantic. It was replaced by “Sara.”

Sandy also did something very few storms do: alter the criteria for issuing hurricane watches and warnings. Despite losing its tropical characteristics while about 50 miles off the coast of New Jersey, Sandy was still forecast to head for the Garden State and was still expected to pack a wallop. For this reason, it was controversial when the NHC stopped issuing advisories for the storm; even though Sandy no longer met the definition of a tropical cyclone at the time, the northeast was about to end up as one of the hardest-hit areas along the storm's path.

As a result of this fiasco, NOAA adopted a new policy that allows the NHC to continue issuing formal advisories on post-tropical cyclones as long as they pose a significant threat to life and property. The new procedure also allows the NWS to keep hurricane and tropical storm watches and warnings active for such storms, despite them no longer meeting either definition.

Are More Superstorms on the Horizon?

While a few superstorms have occurred since 2012, including Hurricane Dorian in 2019, scientists remain uncertain about whether or not they'll become more frequent in future climates. This is largely because so little research relating hurricane size to global warming exists. One of the few studies on this topic was presented at the American Meteorological Society's 33^rd Conference on Hurricanes and Tropical Meteorology in 2018 by research scientist Ben Schenkel of the University of Oklahoma. According to Schenkel's model projections, Atlantic tropical cyclones could grow 5-10% bigger in future climates.

On a related note, scientists do project that tropical cyclones around the world will grow more intense due to global warming — up to 10% more intense.