On the evening of Wednesday, September 1, 2021, the remnants of Hurricane Ida reached New York. Although the storm had been reclassified as a post-tropical cyclone by that point, it smashed the City’s record for the most single-hour rainfall, caused widespread flooding and hundreds of millions of dollars of damage, and took the lives of 13 people within New York City. On September 5, 2021, President Joseph R. Biden, Jr. issued a major disaster declaration for the State of New York (4615-DR-NY). On March 22, 2022, the U.S. Department of Housing and Urban Development (HUD) announced that New York City will receive $187,973,000 in funding to support long-term recovery efforts following Hurricane Ida. This allocation was announced in the Allocations for Community Development Block Grant Disaster Recovery and Implementation of the CDBG-DR Consolidated Waivers and Alternative Requirements Federal Register Notice (Vol. 87, No. 100, 5/24/2022, 87 FR 31636) with funds made available through the Disaster Relief Supplemental Appropriations Act, 2022 (Public Law 117-43).
The storm’s sustained rainfall overwhelmed the City’s sewer system, which typically has the capacity to handle 1.75 inches of rain per hour. As a result, water accumulated in streets and cascaded into the subway system, cellars, and basements particularly in inland areas outside of the 100-year floodplain. Based on the City’s analysis of damaged properties, only 6.9% of Ida-impacted buildings are in the 100-year floodplain, and 13.7% are in the 500-year floodplain.
The City estimates approximately 33,500 buildings sustained damage, about 3.3% of all buildings in the city. While Ida’s impact was felt throughout all five boroughs, the storm was particularly impactful in the outer boroughs. The storm also had a disproportionate impact on residential properties.
While the severity of damage was lower than previous storms, such as Hurricane Sandy, the inland nature, the scale of the damage across the outer-boroughs, and the swiftness of the rainfall represent a dramatic shift in how the City responds to, and prepares for, severe weather events.