Why New York City was caught off guard by flash flooding

Last week, scenes of extreme flooding in New York City made the rounds on social media, with parts of the city and Long Island appearing underwater as the intense rainfall overwhelmed the city's drainage system. Much of the area was under flash flood warnings as the record rainfall seeped into the subway system and stranded commuters around the city in an unprecedented storm. 

The intense rainfall marked the most rain in a single day at New York’s John F. Kennedy International Airport, which saw nearly 8 inches of rain in one day, more "than any other since 1948," per The Washington Post. Brooklyn was hit with about a month's worth of rain in three hours "as it was socked by some of the storm’s most intense rainfall rates," the outlet added. The extreme precipitation prompted New York Gov. Kathy Hochul (D) to declare a state of emergency, calling the rainfall "a life-threatening event,” per The New York Times. While some have positioned the storm as a real-time example of climate change, others feel strongly that human error and interaction also played a direct role in the magnitude of the damage.

Climate change is outpacing the city's preparedness

New York City's infrastructure was built for weather patterns of the past, and those designs did not account for the recent extreme rainfall and flash flooding caused by Hurricane Irene, Hurricane Sandy, or, more recently, Hurricane Ida. “We now have in New York something much more like a tropical-rainfall pattern,” Rohit Aggarwala, New York City’s environmental protection commissioner, said at The Atlantic Festival hours before the storm hit. When designing infrastructure, “you always build to the record,” Aggarwala noted, but that becomes complicated when climate change creates conditions that break those records. 

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“This changing weather pattern is the result of climate change, and the sad reality is our climate is changing faster than our infrastructure can respond,” Aggarwala said, per the Times.  

The big takeaway from the city's sudden deluge is that "our infrastructure was designed for a climate that no longer exists," University of Michigan climate scientist Mohammed Ombadi told Vox. Recent floods have made that point "very clear," as we continue to "hear news of washed-out roadways and bridges, damaged tracks in railroads, and swamped homes," Ombadi added. "We need to change the way we design and build infrastructure to be in line with the increase in rainfall extreme events predicted by climate scientists."

Climate change isn't the only thing to blame

The nationwide trend of unexpected flooding is due in part to "the role the human-built environment plays in exacerbating and sometimes entirely creating these flooding events," Samuel Brody, professor and director of the Institute for a Disaster Resilient Texas, told The Verge. That's what is "playing out in New York City today." Cities need to monitor and update their drainage systems over time. "Historically, in the United States, we’ve done a very bad job of that." Brody also challenged the notion that climate change is advancing too quickly, arguing that "a much quicker, more powerful vector of risk" is that "human development is changing much more quickly than our drainage systems and our infrastructure can accommodate — much more quickly than climate change."

This isn't the first flood to overwhelm the city or affect the city's underground transportation system.  But while climate change has turned "flooding into a more regular, deadly problem for the five boroughs," New York City Mayor Eric Adams "seemed more concerned during the first months of his administration about inundating the subway with cops," Kate Aronoff wrote in the New Republic. And he's not the only city leader slacking: "New York’s governor and Democratic supermajority can’t seem to agree on taxing the rich a little bit more to help deal with climate change."

"It’s long past time for political leaders and citizens alike to prepare differently for such forecasts," said Bloomberg's Mark Gongloff. Some of the billions of dollars that President Biden and Congress allocated for infrastructure last year should "be spent on waterproofing New York and other cities much more thoroughly." As it stands, "it is far too easy to bring one of the greatest cities in the world to a wet, grinding halt."