Current Issue

Apr. 3, 2013

Vol. 113, No. 10


After Sandy

Can Princeton professors help to ­prevent such damage from future storms?

By Anna Azvolinsky *09
Published in the April 3, 2013, issue

Ortley Beach, N.J., was a scene of devastation a month after Hurricane Sandy struck.
Ortley Beach, N.J., was a scene of devastation a month after Hurricane Sandy struck.

Along New Jersey’s Route 37, the traffic begins to thin out and the police checkpoints become more frequent as you approach the bridge linking the mainland to the beachfront communities on the Barnegat peninsula. Only local residents, government officials, contractors, and cleanup crews are allowed to venture near the shore.

It is Thanksgiving weekend, about four weeks after Hurricane Sandy struck the New Jersey and New York coastline, and few residents have returned to Ortley Beach, one of the hardest-hit communities in New Jersey. According to The New York Times, about 10 percent of the 2,000-plus houses were destroyed, and almost all were damaged.

“See that house over there that smashed into the other house? Here is its foundation,” says Ning Lin *10, pointing to a massive hole in the ground that is lined with concrete blocks. She wears a hardhat and neon-colored vest, and stops to snap photos of the damage. Lin, a Princeton assistant professor of civil and environmental engineering, is part of a research team led by Professor Andrew Kennedy of the University of Notre Dame. The researchers have come to Ortley Beach to survey the wind and water damage to homes there and in nearby Seaside Heights.

Devastation awaits them. The famous boardwalk is gone, pieces strewn in every direction. Some buildings have slid 30 feet inland, their foundations left behind. Chunks of black asphalt from a parking lot lie wherever the water and wind left them. They probably came from Joey Harrison’s Surf Club, on the waterfront. The club is standing but severely damaged. A scoreboard hangs on its side. “Surf Club versus Sandy,” someone has written in black marker, with a score underneath: 0 to 1, the storm victorious.

Princeton professors have been studying extreme weather, ­natural disasters, and their impact on people and property for years, but Hurricane Sandy pushed their research to the forefront. No longer was their work theoretical: It now is ­discussed in front-page newspaper stories and in government offices, particularly in and around New York City.

In addition to Lin, an expert on coastal engineering and the impacts of extreme weather, the professors include Guy Nordenson, a structural engineer who is deeply involved with post-Sandy planning in New York City; climate-change expert Michael Oppenheimer, whose work informs planners around the world; and Erik Vanmarcke, who for years has been a consultant to the flood-prone Netherlands. They and several alumni are working to develop tangible strategies to deal with the effects of global warming. Although a direct line cannot be drawn from climate change to Sandy, says Oppenheimer, the director of Princeton’s Program in Science, Technology and Environmental Policy, it is clear that sea levels are rising because of climate change: “There is no doubt about it. That is a one-to-one link.”

In Ortley Beach, the researchers are cataloging the extent of wind and wave damage to 375 houses on several blocks closest to the ocean — checking the damage at each home and determining whether it was caused by wind, windborne debris, or the storm surge. They will identify trends: whether elevation was enough to prevent major damage, what type of building foundations sustained the most damage, and what kinds of building materials were most likely to result in windborne debris that caused damage to adjacent houses. It’s a slow process, but they hope this information can be translated into ways to prevent or minimize damage to residences during future storms — proposals for different building practices and materials, for example. Lin points to a lone house standing a block south of the waterfront. “A combination of construction and location matters,” she says. “Some buildings are better built, with stronger foundations, but were totally destroyed. We want to know why.”

Recently, Lin has been working on mathematical risk assessments of the types of hurricanes we can expect in the next several hundred years. Her model simulates many storms — of different intensities and sizes — under a range of climate conditions, and predicts how likely they are to occur.

The findings by Lin and her Princeton colleagues are sobering. In 2010, the researchers — Lin, ­atmospheric-science professor Kerry Emanuel, and civil and environmental engineering professors Vanmarcke and James Smith — found that storms making landfall on the New Jersey coast would push water into the angle formed by the New Jersey shore and Long Island. This water has nowhere to go but into Lower Manhattan, where it would cause flooding. Then, in a study published in the journal Nature Climate Change in February 2012, they concluded that warmer temperatures and a 1-meter rise in sea level (predicted to occur sometime within the next 100 years or so) increase the probability of hurricane-related storms and higher storm surges in New York City.

How often might such dangerous storms occur? The term “100-year storm” doesn’t mean, as many people believe it does, that such a storm will occur only once in a century. Rather, it describes probability: Such a storm has a 1 percent chance of occurring in any given year. Hurricane Irene was considered a 100-year storm, for example, and yet Sandy struck a year later.

“[We] found that what we used to think of as a 100-year storm, now, under climate-change conditions, may be more like a 20-year storm,” says Vanmarcke, meaning there is a 5 percent probability of it occurring in a given year. “The recurrence is faster, the risk is higher, and the likelihood of storms in any one year may have increased as much as five-fold,” he says. What has been seen as a 500-year storm likely would occur once every 25 to 240 years by the end of this century, the study found.

The researchers are continuing to model hurricanes, incorporating data on recent hurricanes in Florida, Louisiana, and North Carolina. A detailed database that includes wind-speed patterns, and information on wind pressure and the breadth of the winds, is being collected nationally. The worst-case storms Lin is modeling have a storm surge of more than 4.5 meters, or 14.8 feet, at high tide.

Vanmarcke points out that the damage caused by Sandy — the largest storm recorded in the Atlantic Ocean — “really highlights the vulnerability” of New York City. Sandy, which combined high wind speed with very low pressure when it merged with a weather system from the west, was barely a category-1 hurricane, and yet the storm surge was strong: about 2.8 meters, or 9.2 feet, in New York City. The water level observed at the Battery, the southern tip of Manhattan facing New York Harbor, was almost a meter higher than the previous record, set by a hurricane in 1960.

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CURRENT ISSUE: Apr. 3, 2013