At least nine people have died after flash flooding and tornadoes hit the north-eastern US, local media report.
Some people were trapped in flooded basements of their homes, while one body was found in a vehicle that was swept away.
The governors of New York and New Jersey declared a state of emergency, and New York City Mayor Bill de Blasio called it a "historic weather event".
At least 3in (8cm) of rain fell in just one hour in New York's Central Park.
Almost all New York City subway lines have been closed, and non-emergency vehicles banned from roads. Many flights and trains out of New York and New Jersey have been suspended.
The mayor of the city of Passaic in New Jersey, Hector Lora, told CNN the body of a man in his 70s had been recovered from a vehicle that had been swept away in the floods.
NBC New York has reported that at least one more person died in New Jersey. NBC and AFP reported that seven people had died in New York City, some after becoming trapped in their basements.
A two-year-old boy was among the victims in New York City.
Footage on social media showed water pouring into subway stations and people's homes, and flooded roads.
New York resident George Bailey told the BBC: "Right in the middle of dinner I hear gurgling, and the water's coming up out of the shower drain in our bathroom.
"I went to check the main water line in the utility room, and by the time I walked back into the living room there was nearly a foot of water. It was incredible how fast it came through."
More about: EPA