Triggering Flash Floods in US
A powerful coastal storm wreaked havoc in the New York City Tri-State area, inundating the region with heavy rainfall. This relentless downpour, which persisted from late Thursday night well into Friday night, triggered flash floods, stranded motorists, necessitated street closures, subway suspensions, and caused hundreds of flight delays and cancellations. In neighboring New Jersey, water rescues became a critical operation.
As the flash flood emergency unfolded, New York Governor Kathy Hochul swiftly declared a State of Emergency encompassing New York City, Long Island, and the Hudson Valley. She took to social media to urge citizens to prioritize their safety, emphasizing the importance of avoiding travel on flooded roads.
By Saturday morning, the most intense rainfall had subsided, but the statistics were staggering. New York’s Central Park recorded a total of 5.86 inches of rain, including nearly 2 inches falling within a single hour between 9:00 and 10:00 a.m. EDT on Friday. Reports also indicated more than 9 inches of rain in Brooklyn’s Gowanus and Park Slope neighborhoods.
Meteorologists had been closely monitoring this weather event, warning about the potential for heavy rainfall. AccuWeather’s experts had highlighted the risks of 1.5 to 3 inches of rain per hour, which ultimately materialized on Friday, overwhelming sewer and stormwater systems.
New York City had already experienced a wet month, and this storm pushed the total rainfall for September into rare territory. By 9 a.m. EDT on Saturday, over 14 inches of rain had fallen, marking the second wettest September since records began in 1869. The wettest September on record remains 1882, with 16.85 inches of rainfall.
This storm also shattered daily records. On September 29, Central Park received 5.48 inches of rain, eclipsing the previous record from 1963. At John F. Kennedy International Airport, records dating back to 1948 showed that September 29 became the wettest September day with 8.05 inches of rain.
Meteorologists were ahead of the curve in forecasting this event, issuing warnings about flash flooding as early as Wednesday night. By Thursday, they were alerting the public to the potential for life-threatening flooding caused by 4-8 inches of rainfall in New York City.
In fact, the intensity of the rainfall rivaled that of Hurricane Ida in 2021, which brought major flooding and more than 7 inches of rain to the city on the first day of September that year.
The deluge wreaked havoc during the Friday morning commute, disrupting various modes of transportation in and out of the city. The Metropolitan Transit Authority (MTA) suspended train services at many stations, leading to extensive delays for the few subway trains still operational.
Reports of flooding poured in from all five boroughs, with roads closed, detours in place, and multiple cars stranded with water reaching window levels. Flooding also necessitated the evacuation of the David A. Boody School in Brooklyn.
Although the downpours are expected to diminish by Sunday, residual floodwaters could linger on roadways long after the last raindrop falls. Motorists are urged to exercise caution and avoid submerged streets, as just 6 inches of swiftly moving water can pose a serious threat.
Looking ahead, high pressure will return later in the weekend and into the first week of October, offering a welcome respite from the rain. Sunshine and warm conditions are on the horizon for the upcoming week.
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