Chair's Column: Fifth Anniversary of Hurricane Sandy


Dear students, colleagues, and friends of Geography,

Exactly five years ago yesterday, on October 29, 2012, sea water from Hurricane Sandy slammed New York City, inundating low-lying coastal neighborhoods, flooding homes, businesses, streets, and parks. The death toll in the United States directly attributed to Sandy included 48 in New York, 12 in New Jersey, five in Connecticut, two in Pennsylvania, and five in other states. In the Caribbean, Haiti (54 deaths) and Cuba (11 deaths) were the countries affected the most, and there was one death in Canada (1).

Roughly 400,000 City residents were under mandatory evacuation orders, but only about half complied (2). At least part of the reason for the low compliance was the perception left by  Hurricane Irene, which blew through our region one year prior to Sandy in August of 2011, as a “false alarm” (3). The storm steered to the west of the city, sparing us the worst of the flooding. Other areas including the Catskill Mountains (the source of our city’s water supply), however, were devastated.

This autumn has been a remarkable hurricane season, with some records either tied or broken: the number of category-5 (the highest category) storms making landfall in the US (4); the number of storms in the Atlantic (5); and the farthest east in the Atlantic that we have ever seen a major hurricane. (6). In general, our biggest storms tend to occur between August and October, with a smaller number occurring as early as June or as late as November. Not coincidentally, this corresponds with the official hurricane season in the tropical Atlantic Ocean, the Caribbean basin, and the Gulf of Mexico [].

When we see a Hurricane Sandy or a Tropical Storm Irene that has travelled to New York from southern origins, the tropical connection is obvious. While the physical structure of a tropical system differs from that of mid-latitude storms that typically arrive from the west or southwest, even mid-latitude storms can be influenced by the tropics. In fact, the largest ones often travel along the southeastern seaboard, picking up moisture and energy from warm ocean waters, and then travel up the coast. Other times a tropical storm can, during its journey northward, either take on the structural characteristics of a mid-latitude storm or actually combine with a mid-latitude system. This is what occurred yesterday on the anniversary. These are called “transitional” storms.

All three types of storms—tropical, mid-latitude, and transitional—have the potential to become nor’easters along our coast. These storms don’t come from the northeast as many people assume—the name is actually a reference to the direction from which the storm’s wind blows due to its counter-clockwise wind pattern.

A number of research publications, including some of my own (7), indicate that our regional hydrological cycle was more active and extreme between the mid-1990s and 2012 than at any time since meteorological measurements were commonly made starting in the late 19th century. If data inferred from tree rings is taken into account, this may be the stormiest, wettest period in the last 500 years. Much of the scientific analysis suggests that we are likely to get bigger storms in the future (8).

Research lead by our own Professor William Solecki suggests that Irene marked a turning point in the Catskills (9), and Sandy marked a turning point in the city (10), that shifted public and official opinion towards acceptance of climate change and towards allocation of resources for better preparation for the future. Some of the hardest hit areas, such as on Staten Island, remain abandoned or are still struggling to recover (11). While there have been efforts around the city to begin preparing our city to withstand the worst impacts of future events, much of what needs to be done remains in the planning stage (12).

While some of those efforts involve hard engineering such as fortifying hospitals, power plants, subways, and other critical infrastructure, some involve “green infrastructure” by which natural features are used either instead of or in conjunction with high tech and traditional civil engineering strategies to reduce environmental impacts. Perhaps the most ambitious is “The Big U”, a plan to build up the southern tip of Manhattan with easily accessible parkland that would provide recreation most of the time, but fortify the city against flooding during storms (13). Another project run by the Nature Conservancy, along with the Jamaica Bay-Rockaway Parks Conservancy, National Park Service, and hundreds of volunteers, involves covering 14 acres of the Jamaica Bay Wildlife Refuge with trees and shrubs (14) to help mitigate future flooding .

One of the biggest issues here in the city is related to combined sewage overflows (CSOs), which occur during big storms when the flow rate in our sewer system exceeds the capacity of our water treatment facilities, resulting in sewage going directly into the waters around New York City. The NYC Department of Environmental Protection has a green infrastructure program to mitigate the worst impacts related to flooding and water quality (15). A very nice demonstration project that is well worth a visit can be found at the Brooklyn Botanic Garden’s Water Conservation Project (16). The main component is the Water Garden, which consists of a pond and brook system, along with a small wetland and riparian environment with plants chosen for their ability to filter water, promote more absorption, improve water quality, and slow the flow. In addition to these natural features, the project includes a high tech component that utilizes a computerized system  to monitor pond depth, automatically receive weather forecasts from the National Weather Service, and then lower the pond’s depth prior to big storms so that the garden can absorb more water, helping to diminish the magnitude and duration of CSOs.

Under the Bloomberg administration the city came up with a comprehensive plan to improve the resiliency of the city called PlanNYC (17). Mayor De Blasio’s plan, OneNYC, has been updated with an expanded focus on equity (18). Lets hope that these efforts can lead to a more equitable and resilient city.

Allan Frei
Chair, Department of Geography, Hunter College
CUNY Institute for Sustainable Cities


  7. Frei, A., Kunkel Kenneth E., Matonse Adao, 2015, The Seasonal Nature of Extreme Hydrological Events in the Northeastern United States, Journal of Hydrometeorology, V16, No. 5, p. 2065-2085, doi:10.1175/JHM-D-14-0237.1
  9. Solecki, William, Allan Frei, Susan Sofranko, Simon Gruber, Adao Matonse, Lesley Patrick, Robin Leichenko, and Michael Brady, 2014, Hydrology, vulnerability and adaptation implications of Hurricane Irene and Tropical Storm Lee: Case study of the Mid-Hudson Valley and Greater Catskills Regions, New York State Energy Research and Development Authority Report Number 14-40.
  10. Solecki, W. and C. Rosenzweig (2014). "Climate change, extreme events, and Hurricane Sandy: From non-stationary climate to non-stationary policy." Journal of Extreme Events 1(1): 1450008 DOI: 10.1142/S2345737614500080