Record-breaking rainfall swamps New York City, causing widespread urban flooding

Record-breaking rainfall submerged streets and disrupted travel across the New York City metropolitan area on September 29, 2023. The deluge set new daily records and made this month the wettest September in New York City’s recorded history.

Heavy rains disrupted daily life in the New York City metropolitan area, causing severe urban flooding that stranded motorists, led to the closing of roads and subways, and grounded hundreds of flights. On September 29, JFK Airport registered 202.7 mm (7.97 inches), Central Park 139 mm (5.47 inches), LaGuardia Airport 104.1 mm (4.10 inches), and Bridgeport Airport 43.7 mm (1.72 inches), establishing new daily records for the date. These measurements there began in 1882.

Further reinforcing the extraordinary conditions, Central Park recorded nearly 50.8 mm (2 inches) of rainfall in just one hour between 09:00 and 10:00 LT. AccuWeather Chief Meteorologist Jon Porter stressed that the rate of rainfall was a significant factor, noting that downpours at the rate of 38 to 76 mm (1.5 to 3 inches) per hour are too much for sewer and stormwater systems to handle.

In response to the flooding crisis, New York Governor Kathy Hochul declared a State of Emergency for New York City, Long Island, and the Hudson Valley. The advisory urged residents to stay safe and avoid flooded roads.

New Jersey also faced challenges, as water rescues were reported due to flash flooding in the state.

Reflecting on the larger context, the month of September 2023 has set records for rainfall in New York City. JFK Airport recorded 330.4 mm (13.01 inches), or 363% of normal precipitation levels for the month, making it the wettest September on record. Similarly, LaGuardia reported 324.3 mm (12.76 inches), or 329% of normal, and Central Park logged 361.9 mm (14.25 inches), or 331% of normal. These figures represent a significant outlier in New York City’s climatological history, with Central Park’s data indicating that this was the second-wettest September on record.

The historical perspective is also noteworthy. The wettest day for the Central Park area remains September 23, 1882, when 210.3 mm (8.28 inches) of rain was measured in a 24-hour period, followed by April 15, 2007, with 192.3 mm (7.57 inches).

While September 2023 had average temperatures throughout New York, the dominant weather story was unquestionably the excessive rainfall.

Crews are on duty throughout the night handling flooded roads, clearing debris, and fixing traffic signals after torrential rain on Friday for a safe & clear Saturday. #LIwx #NYwx pic.twitter.com/fkmPPN2qAl

— NYSDOT Long Island (@nysdotli) September 30, 2023

Friday has been a wet one! @NYSDOT crews are dispatched across Long Island to handle any floods, downed trees, or other wet hazards.
Pumping has been underway to clear water from the Northern State Parkway near the Meadowbrook State Parkway. #LIwx #NYwx pic.twitter.com/GFfUqqObgD

— NYSDOT Long Island (@nysdotli) September 29, 2023

New York: The rain isn’t over yet. It is extremely dangerous to travel on flooded streets.

As rain continues to impact downstate areas throughout the day, don’t attempt to walk, bike, or drive in these conditions.

Stay safe. pic.twitter.com/gGeCShKR87

— Governor Kathy Hochul (@GovKathyHochul) September 29, 2023

Our Office of Fire Prevention and Control’s flood rescue teams are on the ground in Westchester County to assist local emergency response.

📸: OFPC Swift Water Team on the ground in New Rochelle, NY checking vehicles. pic.twitter.com/3UJjr4khdO

— NYS Div. of Homeland Security & Emergency Services (@NYSDHSES) September 29, 2023

References:

¹ Data released by NWS office in New York – September 29 – October 1, 2023

² New York City, New Jersey brought to a standstill by flash flooding – AccuWeather – October 1, 2023

Featured image credit: Governor Kathy Hochul (stillshot)