New Jersey Governor Phil Murphy declared a state of emergency, urging people to stay indoors.

Authorities across the region, including in Virginia, Maryland and Pennsylvania, warned of hazardous driving conditions due to the risk of flash floods.

JFK, LaGuardia and Newark airports temporarily suspended departures on Monday night, forcing the cancellation of dozens of flights.

Rescue workers in Scotch Plains, New Jersey waded into gushing floodwaters armed with red flotation devices after several drivers became stranded in the sudden surge, according to footage from CBS.

In New York City, video shared on social media showed muddy brown water spewing like a geyser in front of a subway station's turnstiles.

Multiple subway lines were briefly suspended or running with delays, while above ground, massive traffic jams paralyzed several of the city's main thoroughfares.

The National Weather Service (NWS) urged drivers encountering flooded roads to "turn around."

"Most flood deaths occur in vehicles," it said.

A flood warning remained in effect until Tuesday morning for parts of New Jersey, while the slow-moving storm was expected to continue depositing heavy rain on the US Mid-Atlantic region into the middle of the week, according to the NWS.

"The greatest concentration of storms will be across the southern Mid-Atlantic/Appalachians on Tuesday and shift northward with the boundary into the central Mid-Atlantic/Appalachians on Wednesday," the government forecaster said.

More than two inches of rain drenched several urban areas in less than two hours.

New York's Staten Island recorded between 4 to 6 inches (10 to 15 centimeters) of rain on Monday night, according to the city's emergency notification system.

Zohran Mamdani, the Democrat running for mayor of New York City, wrote on social media that the rapid flooding emphasized the need for climate-proofing the city.

"We must upgrade our infrastructure for this new climate reality," he wrote.