Pinpointing the Unlikeliness of Ida’s New York City Hourly Intensity: Climate Change, Non-Stationarity, and Extreme Precipitation
Authors
Naresh Devineni1,2* (ndevineni@ccny.cuny.edu), Carolien Mossel1,2, Spencer Hill1,2, Nihar Samal3, James Booth1,2
Institutions
1The City University of New York Graduate Center, New York, NY; 2The City University of New York–City College, New York, NY; 3New York City Department of Environmental Protection, New York, NY
Abstract
The remnants of Hurricane Ida caused major damage and loss of life in the northeastern United States on September 1st, 2021. Over 40 people died in the storm across the United States, 11 of whom died in flooded basement apartments within New York City. The storm was so catastrophic because the maximum hourly precipitation intensity, recorded as 3.47 inches at Central Park, was unprecedentedly high for the region. The team contextualizes this storm’s unprecedented nature within the historical record and projects its risk in terms of likeliness of occurrence and consequences in the near- to medium-term future using stationary and nonstationary hazard analyses techniques. The project shows that there is a multifold increase in the expected future risk when nonstationary models conditioned on future temperature projections are used as opposed to stationary models that assume no climate change. These results can be translated to potential future damage costs to the city by planning for events that would be expected under climate change. The results also reinforce the pressing need for improved urban stormwater management systems that can handle higher intensity rainfall as climate change continues to impact the weather and subsequently urban cosmos.