Record rain in New York City generates 'life-threatening' flooding, overwhelming streets and subways

Record-setting rain overwhelmed New York City's sewer system Friday, sending a surge of floodwater coursing through streets and into basements, schools, subways and vehicles throughout the nation's most populous city.

The water rose fast and furious, catching some commuters off guard as they slogged through Friday morning's rush hour. First responders jumped into action where needed, plucking people from stranded cars and basements that filled like bathtubs.

More rain fell in a single day at New York's John F. Kennedy International Airport - nearly 8 inches - than any other since 1948. A month's worth of rain fell in Brooklyn in just three hours as it was socked by some of the storm's most intense rainfall rates Friday morning.

Track travel delays: NYC airports hammered with heavy rain and flooding

The prolific totals are a symptom of climate change, scientists say, with a warmer atmosphere acting like a massive sponge, able to sop up more water vapor and then wring it out in intense spurts which can easily overwhelm outdated flood protections.

"Overall, as we know, this changing weather pattern is the result of climate change," Rohit Aggarwala, New York City's Chief Climate Officer said in a Friday morning news conference. "And the sad reality is our climate is changing faster than our infrastructure can respond."

A widespread 3 to 6 inches of rain had fallen across the New York City by late Friday afternoon. More rain will fall through the evening, though it will gradually taper off.

New York Gov. Kathy Hochul declared a state of emergency for New York City, Long Island and the Hudson Valley Friday morning as the worst of the flooding hit. In an interview with New York's WNBC-TV she urged residents to stay home because of widespread dangerous travel conditions.

"This is a very challenging weather event," Hochul said. "This a life-threatening event. And I need all New Yorkers to heed that warning so we can keep them safe." New Jersey Gov. Phil Murphy also declared a state of emergency for his state Friday afternoon.

Firefighters performed rescues at six basements in New York City flooded by torrents of water, according to the New York City Fire Department.

The water also found its way into 150 of New York City's 1,400 schools, which remained open on Friday, New York City school chancellor David Banks said at a news briefing.

One school in Brooklyn evacuated when floodwater caused the school's boiler to smoke, he said.

"Our kids are safe and we continue to monitor the situation," Banks said.

Floodwater spilled into subways and onto railways and caused "major disruptions," including suspensions of service on 10 train lines in Brooklyn and all three Metro-North train lines. Gov. Hochul said the city was deploying additional buses to help fill the gap caused by the train outages.

Air travel didn't fair any better. Flight delays hit all three New York City area airports Friday. Flooding inside the historic Marine Air Terminal in New York's LaGuardia airport forced it to close. The terminal is the airport's smallest and serves Spirit and Frontier airlines.

A travel advisory remains in effect for New York City through 6 a.m. ET Saturday with more flooding possible.

The New York tri-state area is facing a Level 3 of 4 "moderate" risk for flash flooding for the rest of the day Friday, the National Weather Service warned.

The flood threat stretches beyond New York City and impacts roughly 25 million people across the Northeast.

Heavy rain will expand north and east and impact a wide swath of southern New England through Friday evening. The heaviest rain in the region will center on Connecticut, where flash flood warnings were already in place on Friday afternoon. Rainfall of 3 to 4 inches slammed the southwestern portion of the state earlier Friday.

One to 3 inches of rain is also possible from central Connecticut to portions of Rhode Island through Friday evening. Parts of Massachusetts, including Boston, could tally up widespread rainfall totals of 1 to 2 inches by the time the heaviest rain comes to an end Friday night.

The extreme rainfall rates over have produced prolific totals:

Correction: A previous version of this story misstated when the NYC travel advisory went into effect. It was 2 a.m. ET.

CNN's Brandon Miller, Zenebou Sylla, Samantha Beech, Paul Murphy and Nicki Brown contributed to this report.