Flash Flood — Bronx, New York

2021-09-01 · near Fordham, Bronx, New York

Event narrative

The Bronx River at the New York Botanical Garden rose above its minor flood stage of 3.0 feet at 10:15pm EDT. It then continued to quickly rise, surpassing moderate flood stage (3.5 feet) at 10:45pm EDT and major flood stage (4.0 feet) at 11:30pm EDT. The river ultimately crested at a height of 5.59 feet at 8:45am EDT on September 2nd. It eventually fell back below minor flood stage at 9:30pm EDT on September 2nd.

Wider weather episode

Extremely heavy rainfall associated with the remnants of Hurricane Ida overspread southeast New York during the evening of September 1 and continued through the early morning hours of September 2. Rainfall totals ranged from 5-8 inches across much of the region, with much of that rain falling in just a few hours. The ASOS at Central Park recorded 7.19 inches of rain, including 3.15 inches in a single hour between approximately 9:00-10:00pm. This resulted in widespread catastrophic flash flooding across New York City that resulted in extensive road and subway closures and numerous water rescues. Additional rainfall totals from around the region include 7.38 inches at a New York Mesonet station in Fordham in the Bronx, a report of 7.00 inches from a CoCoRaHS observer in Boerum Hill, Brooklyn, 6.90 inches from the ASOS at LaGuardia Airport, a spotter report of 6.18 inches in Monroe, a spotter report of 8.09 inches in Scarsdale, and a CoCoRaHS report of 6.72 inches in Locust Valley. Ultimately 17 people died as a result of the flash flooding, including 13 in New York City and 4 in the Lower Hudson Valley.

View location on OpenStreetMap → (40.8640, -73.8771)

Source: NOAA Storm Events Database, event_id 987623. Narrative written by the NWS forecast office that issued the report.