At least six people have been killed after Storm Ida dumped a month’s worth of rain on parts of the US.
Four of those who died were in New York City, while the other two were in New Jersey, according to NBC.
A state of emergency has been declared in both states after the remnants of a hurricane sparked flash floods, with subway services in New York City suspended.
Last night, New York City suffered its wettest hour on record, with more than 80mm of rain falling in Central Park in the space of 60 minutes.
That eclipsed the previous record of 49mm that was set in the aftermath of Tropical Storm Henri just last month.
Parts of Connecticut are also under a flash flood warning.
The casualties include a 19-year-old who was found dead at a flooded block of flats in Rockville, New Jersey, where water had almost reached the ceilings of the basement.
The New York City Fire Department said it responded to a report of flooding in Queens shortly after 11pm and one person taken from the building was pronounced dead.
Another victim in Passaic, New Jersey, was found dead in a vehicle that went underwear when it was caught in floodwaters near the Passaic River, according to the town’s mayor.
The National Weather Service said Wednesday was the first time it had issued a “flash flood emergency” for New York City.
The term is used for exceedingly rare situations in which a flash flood is posing a severe threat to human life and causing catastrophic damage – or will do so soon.
“We’re enduring a historic weather event tonight with record breaking rain across the city, brutal flooding and dangerous conditions on our roads,” New York City Mayor Bill de Blasio said.
He urged people to stay off the streets, saying: “If you’re thinking of going outside, don’t. Stay off the subways. Stay off the roads. Don’t drive into these heavy waters. Stay inside.”
A travel ban that barred non-emergency vehicles from streets and highways was issued until 5am ET (10am BST).
New York City Subway tweeted that anyone trapped between stations should stay put as video emerged showing riders that appeared to be stuck on trains.
The city’s LaGuardia and JFK airports reported flight disruptions, while New Jersey’s Newark airport limited its operations after initially suspending all flights.
At least one tornado hit New Jersey, with posts on social media showing houses reduced to rubble by strong winds.
When Ida made landfall in Louisiana as a hurricane at the weekend, it left the city of New Orleans without electricity and caused huge amounts of damage.
The latest wave of devastation caused by Hurricane Ida comes as the UN warned that weather disasters are striking the world four to five times more often and causing seven times more damage than in the 1970s.