Two people were killed in New Jersey during flash flooding as severe storms lashed the New York City area, submerging cars and flooding subway stations.

The intense rainfall caused widespread travel disruption across the region's airports, highways and railways on Tuesday.

More than 5 cm of rain was recorded in a single hour in Manhattan's Central Park, the second most for a 60-minute period in history, according to Mayor Eric Adams.

Videos showed flooding in several subway stations on Monday evening, including a geyser of water spewing into a station on Manhattan's West Side.

Officials said the subway system was simply overwhelmed by the amount of rainfall in such a short amount of time.

The antiquated sewer system can handle around 4.44 cm of rainfall per hour, Rohit Aggarwala, the city's environmental protection commissioner, told reporters on Tuesday, compared with a rate of more than 4 inches an hour at the storm's peak.

"I probably don't recall seeing that level of rain before," Adams said.

New Jersey Governor Phil Murphy declared a state of emergency and said two people died in Plainfield when their vehicle was swept away by floodwaters.

The victims were found in a submerged car, Murphy told reporters.

Murphy said that some places got 15.25 cm of rain in less than 2.5 hours and that it appeared some locations experienced flooding for the first time.