Late on October 29, 2012, one of the largest storms in recorded history hit the East Coast of United States. Although Hurricane Sandy centered around New Jersey and New York when it made landfall, the massive storm system spanned 1,000 miles north to south, over three times the size of a typical hurricane.
This “once-in-a-lifetime” storm event came one year after Tropical Storm Irene, which itself caused over $19 billion in damage. The confluence of Sandy’s size, its concurrence with a full moon tide and a high pressure system to the east keeping the storm close to the coast resulted in substantial disruptions for over 60 million people.
Boston, with its sheltering harbor and distance from the storm center, experienced relatively minor coastal flooding (see below).
Flooding at Boston's Fort Point Channel during Hurricane Sandy. Photo by Danielle Pillion.
Unfortunately New York City fared far worse. Onshore winds pushed a record 14-ft. storm surge down Long Island Sound onto the streets of lower Manhattan. Over a million people were left without electricity, the largest power outage in the city’s history. New York’s tunnels, subways, waterfront and financial district were flooded with corrosive seawater.
Flooded cars in NYC's Financial District during Hurricane Sandy. Photo by Andrew Burton.
Early estimates of Hurricane Sandy’s costs approach $50 billion, with $20 billion in insured property damages and $10 to $30 billion in lost productivity.
Although Boston avoided the worst of Sandy’s effects, our sister city did not. We can and must learn from New York’s experience to make our waterfront, downtown and infrastructure more resilient to coastal flooding.
Older East Coast cities were not designed to withstand the level of flooding seen in Hurricane Sandy or expected over the next century with high sea levels. “The way New York was designed, we’re not in a part of the country that deals with floods or [is] designed to deal with floods,” said New York Governor Andrew Cuomo. “We have a lot of infrastructure under the ground that gets filled up. The subway tunnels have all flooded. Some of the subway stations, the water is up to the ceiling.”
The fact that Boston missed New York’s fate was more luck than planning. The State of Vermont, for example, suffered catastrophic damage to buildings and infrastructure during Tropical Storm Irene, but was largely bypassed by Hurricane Sandy. This is something the City of Boston is taking very seriously, and has already begun incorporating both climate change mitigation and adaptation into its policies and plans. But no East Coast city is yet prepared for another superstorm like Sandy or for future sea levels, predicted to be as much as six feet higher by 2100.
If the maximum storm surge arrived just four hours earlier than it did, the Boston waterfront would have experienced significant flooding The map shown below, developed for TBHA's 2010 Sea Level Rise Forum, indicates the areas in Boston that would have been flooded by up to two feet (in yellow) and up to four feet (in red) if the storm surge had hit during the full moon high tide instead of four hours later.
Although the exact timing of climate change-related sea level rise remains uncertain, the trajectory is clear. Ocean levels are rising, not dropping. Storms are getting more severe, not less. “I think at this point it’s undeniable that we have a higher frequency of these extreme weather situations, and we’re going to have to deal with it,” Governor Cuomo argued.
Decisions New York City made ahead of and during the storm to protect its infrastructure prevented additional damage and decreased the recovery time. The City of New York made the decision both during Tropical Storm Irene and Hurricane Sandy to preemptively shut down the MTA system and send all subway cars to high ground. Consolidated Edison, the electrical utility serving Manhattan, shut down power ahead of the storm to prevent additional damage from floodwaters hitting live wires and transformers.
By preparing for sea level rise now and over time, we hope to increase our resilience to the type of catastrophic flooding New York has already experienced. Thanks to generous support from the Barr Foundation, The Boston Harbor Association is working with researchers from UMass Boston and UNH to help policy makers, property owners and the public understand where Boston is most vulnerable to coastal flooding and how we can most cost effectively make our waterfront and downtown more resilient to the rising tide.