41 people are confirmed dead in the aftermath of Hurricane Ida in what officials are calling a "historic" weather event.

Police and local authorities said there were 15 dead in New York City and its suburbs, and three others near Philadelphia.

In neighboring New Jersey, Governor Phil Murphy expressed his "sadness" that "at least 23 New Jersey residents lost their lives" in the hurricane.

Record rainfall, which prompted New York authorities to issue an unprecedented declaration of a state of emergency caused by floods, turned streets into rivers, while suspended subway stations were also inundated, and railroads inundated.

"I'm 50 years old and I've never seen this much rain," said Mitodeja Mihaglov, whose basement of his Manhattan restaurant was submerged in 76 millimeters of water.

"It's like we live in the jungle, it's like a tropical rain. It's unbelievable. Everything is weird this year," he told AFP.

Hundreds of flights were canceled at LaGuardia and John F. Kennedy airports, as well as Newark, which showed a video of one of its buildings submerged in water.

"We are together (in the face of the hurricane). The state is ready to help," US President Joe Biden said ahead of an upcoming visit Friday to the southern state of Louisiana, where Hurricane Ida earlier destroyed buildings and cut power to more than a million homes.

The floods closed major roads in several neighborhoods, including Manhattan, the Bronx and Queens, while emergency services rescued hundreds of people.

Several people died in New York City, including eight who were unable to escape from the basements of buildings in Queens and Brooklyn, police said. The ages of the victims ranged between two and 86 years.

"Among the people most at risk during flash floods here are those who live in informal homes on basements that do not comply with the safety standards needed to be rescued," Representative Alexandria Ocasio-Cortez said in a tweet.

"These are working class, immigrants, low-income people and their family members," she added.

Four people were killed in Elizabeth, New Jersey, where a state of emergency was also declared, a spokesman for the mayor told AFP, while another death was confirmed in Passaic.

Three people were also killed in Montgomery County, outside Philadelphia, Pennsylvania, according to a local official.

Hurricane Ida hit southern Louisiana at the weekend, causing massive flooding and hurricanes while wreaking havoc in the north.

New York Mayor Bill de Blasio tweeted, "A historic event in weather tonight that brought record rain across the city, massive flooding and dangerous conditions on our streets."

A state of emergency was declared in New York and New Jersey, while the National Weather Service issued the first-ever flash flood warning in New York City, calling on residents to head for heights.

"You don't know how deep the water is and the situation is very dangerous," the New York branch of the National Weather Service said on Twitter.

- Hurricane threat continues

-The sky appeared clear in New York on Thursday morning, and life gradually returned to normal in the city, while the effects of the previous night's disaster were visible. Residents pushed branches that had fallen off the roads, while metro services slowly resumed.

About 98,000 homes were out of power in Pennsylvania, 60,000 in New Jersey and 40,000 in New York, according to the "Power Outage.US" website.

The northeastern coast of the United States rarely experiences storms like these. The storm comes as ocean surface temperatures rise due to climate change.

Scientists note that warming is making hurricanes more powerful and carrying more water, which represents an increasing threat to coastal populations around the world.

"We are facing global warming and it will only get worse and worse unless we do something about it," Democratic Senator Chuck Schumer said.

In Annapolis, 50 km from the capital of the United States, a tornado smashed trees and brought down electricity poles.

The National Weather Service warned that the threat of tornadoes would remain as they monitored parts of Connecticut, northern New Jersey and southern New York, as Ida headed north through New England on Thursday.