The torrential rains that tropical storm Ida brought over the Northeast of the United States on Wednesday and Thursday have once again exposed how vulnerable our infrastructure is to extreme weather events that are becoming more frequent due to climate change. The storm left a trail of destruction across New York, New Jersey and Pennsylvania, killing more than three dozen people, many of them found in basement apartments flooded after the extreme rainfalls.
According to data from the Iowa State University’s Iowa Environmental Mesonet (IEM), Wednesday nights rainstorm shattered previous precipitation records in the region, with New York City just one example. In the hour from 8:51 PM to 9:51 PM on September 1, the Central Park ASOS (Automated Surface Observing System) registered 3.15 inches of rain in one hour, shattering the previous record set by the Hurricane Henri just 11 days earlier.
As the following chart shows, the remnants of Hurricane Ida brought downpour exceeding the previous record by more than 60 percent, explaining the images of flash floodings across New York City that went around the world.
This chart shows the maximum hourly precipitation events in New York City from 1943 to 2021 (as of September 9, 2021).
