- On Wednesday afternoon, New Yorkers encountered a fully submerged subway station in Williamsburg, Brooklyn.
- One commuter tweeted a photo of the flooded stairs and asked the Metropolitan Transportation Authority to explain.
- The MTA said it flooded the platform for four hours to test a new flex gate that would “seal off a subway entrance.”
- The MTA added: “We’re doing this because climate change is real.”
- In 2012, Superstorm Sandy flooded nine subway stations and two interborough tunnels, causing billions of dollars’ worth of damage. As our planet warms, superstorms and hurricanes are expected to get stronger and wetter.
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On Wednesday, Kaye Blegvad was stymied in boarding the G train at the Broadway Station in Williamsburg, Brooklyn.
The entrance and stairs to the subway platform at the corner of Broadway and Union Avenue were underwater, and there wasn’t a rain cloud in sight.
“The other subway entrances were dry and normal, and nobody seemed to be freaking out, so I just got on the train,” Blegvad told Quartz. “Only once I was on the train did I start thinking, wait, that really was quite insane.”
Later that afternoon, she posted a picture of her curious subway encounter on Twitter and asked the Metropolitan Transportation Authority to explain.
The MTA's Twitter account, which provides 24/7 updates about transit services, clapped back: "We're pivoting to submarines."
Joking aside, the MTA quickly followed up with another tweet saying it had purposefully flooded the station for four hours to test a new flex gate, a type of barrier designed to hold back up to 14 feet of water in the event of a flood or rising waters during a superstorm or hurricane.
"We're doing this because climate change is real," the MTA said.
In October 2012, storm surge from Superstorm Sandy flooded nine subway stations with saltwater, submerged two Long Island Rail Road tubes linking Manhattan and Queens, and caused damage throughout the rest of the transit system.
The damage from Sandy is still being repaired, even as the MTA tries to prepare for storms, to the tune of $5 billion.
Preparing for the next superstorm
Seven years ago, Hurricane Sandy spawned over the north Atlantic and hit Category 3 status, with winds reaching 130 mph. By the time it made landfall in New York and New Jersey, it had weakened to a superstorm that spanned 1,000 miles.
With Sandy, it wasn't hurricane-force winds that wreaked havoc in the Big Apple, but the resulting storm surge. The sea level rose far above the tide line, and floodwaters reached nearly 8 feet in parts of the Jersey Shore and 6.5 feet around New York City. It swamped underground subway platforms and tunnels.
At the time, the MTA could only bring sandbags and plywood to shore up vulnerable subway openings.
"We've learned our lesson," Joe Lhota, the MTA chairman at the time, said in 2017, adding that it "won't happen again."
In the years since Sandy, the MTA has put several solutions in place to prepare for the next superstorm, including 3,000-pound, vault-like doors to board up stations closest to the waterline, like those at Whitehall Street and South Ferry in downtown Manhattan.
The MTA also has a system of interlocking "stop logs" that can be stacked at subway entrances, as well as heavy fabric curtains that can block water. More than 2,000 covers are in place to shore up subway grates.
The flex gates, like the one tested at the Broadway Station on Wednesday, are made of Kevlar and light enough so that a single person can install the flood barrier in minutes; 65 have been installed so far, The Verge reported.
The MTA tweeted that the gates were designed to "seal off a subway entrance." The organization also told The Verge there would be more "flood tests" like the one on Wednesday in the future.
"We're investing in capital projects around the system to prepare for the impacts of a changing climate," the account tweeted.
Hurricanes are becoming stronger, wetter, and more destructive
The MTA isn't kidding itself about what the future will bring to New York.
It has said that "with intense weather events like Superstorm Sandy expected to occur more often, we need to act now to protect this vital part of our system, so we can keep trains running safely."
A recent study found that extremely destructive storms like Sandy and Katrina had become far more common in the US relative to their less damaging counterparts.
"We estimate that there has been a tripling in the rate of the most damaging storms over the last century," Aslak Grinsted, the lead author, previously told Business Insider.
While scientists can't directly link individual storms like Sandy to climate change, warming overall makes such storms and hurricanes more frequent and stronger than they would otherwise be.
That's because oceans absorb 93% of the extra heat that greenhouse gases trap in the atmosphere, and hurricanes use warm water as fuel. So a rise of 1 degree Fahrenheit in ocean temperature can increase a storm's wind speed by 15 to 20 mph, according to Yale Climate Connections.
Plus, rising water temperatures lead to sea-level rise, which increases the risk of flooding during high tides and in the event of storm surges. Warmer air also holds more atmospheric water vapor, enabling tropical storms to strengthen and unleash more precipitation.
Generally, a stronger storm brings a higher storm surge. This resulting wall of water can flood coastal cities, as Sandy did in 2012. If a storm's winds are blowing directly toward the shore and the tide is high, storm surges can force water levels to rise as rapidly as a few feet per minute.
But deployment tests like the one Blegvad saw in Williamsburg this week may ensure that future storm surges don't cause the same level of damage as they did during Sandy.
"I am confident that the MTA is more prepared than ever to face storms even stronger than Sandy," Lhota said in an MTA press release last month.