Flash Flooding Submerges Streets And Subways Across The Northeast
Flash flooding across the Northeast on Monday shut down transit systems, submerged roads, and left two people dead in New Jersey, where Gov. Phil Murphy declared a state of emergency. Flood watches remain in effect for parts of Virginia and Maryland.
In New York City, more than 2 inches of rain fell on Central Park in one hour — the city’s second-highest rainfall total ever, just behind Hurricane Ida in 2021.
It overwhelmed the city’s drainage system and flooded subway stations from the Upper West Side to Brooklyn.
The flash flooding was fueled in part by unusually warm Atlantic Ocean waters and climate change.
MORE TO COME
According to Dr. Klaus Jacob, a geophysicist and professor emeritus at Columbia University, these scenes are only going to become more common.
Flash floods are now occurring outside of tropical storms, and more often. Since 1970, hourly rainfall intensity has increased in 90% of major U.S. cities. That’s outpacing what most drainage systems — built for lighter rains — can handle.
All of the top 3 heaviest, one-hour rainfalls in NYC have occurred in just the past four years.
Why? As the climate warms, the atmosphere holds more moisture. “So when that moisture hits a cold front, we get heavier and more frequent downpours,” Jacob told Mo News. The same dynamics — warmer air, more moisture, sudden downpours — are causing flash floods from Texas to Maine.
During hurricanes, forecasters can predict where the storm will hit and about how much rain will fall, but flash floods caused by localized downpours can strike anywhere, even at higher elevations.
THE COST OF MITIGATION
Because of how widespread the flash flooding issue is, Metropolitan Transportation Authority (MTA) Chairman Janno Lieber told PIX11 News that these type of flash flood delays are “the new reality” as city officials work on long-term solutions.
New York City's drainage infrastructure — much of it built over 100 years ago — was not designed for today’s climate. If more than 1.75 inches of rain falls in one hour across the city, the drainage system starts to get backed up overwhelming streets and subway stations.
The MTA has noted that its infrastructure is not designed to withstand increasingly extreme weather, especially flash floods. They are asking for the city to invest and expand drainage infrastructure.
"The subway system wasn’t built to be a sewer, but in a storm, that’s what it becomes," Jacob said. “The flooding starts on the street, and the subway just happens to be underneath.”
On Monday night, the MTA said it pumped 16 million gallons of water from New York City’s subway tunnels.
Solutions costs $$: The MTA has requested an additional $6 billion for stormwater and coastal flood resilience projects. According to New York City’s chief climate officer, it will actually take about $30 billion to upgrade the most vulnerable parts of the sewer system, but the city currently allocates just $1 billion per year.
Jacob says this funding is "a drop in a very big rain bucket” and warns that “we’ll pay tens of billions now, or hundreds of billions later in damages” down the road if governments in New York and beyond don’t invest more in mitigation measures.
TEXAS UPDATE
These types of flash floods devastated central Texas on July 4, killing more than 130 people. Around 100 remain unaccounted for, authorities say.
Kerr County Sheriff Larry Leitha said Monday that search and recovery efforts could take as long as six months. At least 2,200 personnel from multiple agencies have been deployed to assist.
There are also growing questions about FEMA’s response. The agency did not deploy search and rescue teams until at least the evening of Monday, July 7 — days after the last victims were found alive.
Some have reported the delay was due to new bureaucratic hurdles at the Department of Homeland Security where Secretary Kristi Noem has asked to personally sign off on expenditures by her department. Noem has denied there was any delay in deploying search and rescue teams.
