All five boroughs of New York City were under a flood warning, with footage showing subway stations inundated and cars stranded.
Six East Coast airports, including major hubs like JFK, LaGuardia, and Newark, grounded flights, causing significant delays and travel disruption.
Officials in both New York City and New Jersey urged residents to take precautions, advising against unnecessary travel and for those in low-lying areas to move to higher ground.
The National Weather Service predicted continued rainfall, with warnings also issued for extreme heat and further floods on Tuesday.