September 2023 New York floods

September 2023 New York floods

Flash flooding across roadways in Flatbush, Brooklyn, New York
Cause	Heavy rains
Meteorological history
Duration	September 28–29, 2023
Flood
Maximum rainfall	9.80 in (249 mm) in Park Slope, New York
Overall effects
Damage	$100 million (2023 USD)[1]
Areas affected	Southeastern New York, Southwestern Connecticut, Northeastern New Jersey

On September 29, 2023, heavy rainfall led to flooding across portions of the New York metropolitan area and surrounding areas in the United States. The floods were caused by a low-pressure area that had absorbed the remnants of Tropical Storm Ophelia, which then stalled over the New York City area. Multiple rounds of heavy rainfall also moved through the region as a result of favorable precipitable water values, convective instability, and low-level winds. This induced high rainfall totals across northwestern New Jersey, southeastern New York, and southwestern Connecticut, with the highest total reaching 9.80 inches (249 mm) in Park Slope, Brooklyn.

The flooding inundated numerous highways and roads, and affecting all New York City Subway service, suspending and delaying routes and services. Additionally, Amtrak, Metro-North Railroad, and NYC Ferry services were delayed or suspended, and airports across the New York City area experienced service disruptions and flight delays and cancellations, including both a terminal being flooded and a ground stop implemented at LaGuardia Airport. Several attractions, including the Alamo Drafthouse in three locations and the Prospect Park Zoo, were closed as a result of the flooding. Heavy rainfall inundated schools and forced multiple festivals to be postponed across the affected areas. Flooding also occurred across numerous towns and municipalities across New Jersey and Connecticut, causing the Housatonic River to swell in western portions of the latter state.

In the aftermath of the flooding, New York governor Kathy Hochul declared a state of emergency for the five boroughs of New York City, as well as portions of the Hudson Valley and Long Island. New York City mayor Eric Adams and Hoboken, New Jersey mayor Ravinder Bhalla also declared states of emergency, while New Jersey governor Phil Murphy declared a state of emergency for all 21 counties in the state. Damage from the floods were estimated at $100 million.