A sustained round of torrential downpours after a week of mostly steady rainfall triggered has flash flooding in New York, disrupting subway service in the most populous US city, inundating basements and turning some streets into small lakes.
A flash flood warning was in effect for New York on Friday with as much as 6cm of rain falling in some locations, including Brooklyn, lower Manhattan and John F. Kennedy International Airport in the borough of Queens.
The extreme rainfall prompted New York Governor Kathy Hochul to declare a state of emergency for the city, Long Island, and the Hudson Valley, and some National Guard troops were deployed to assist in the response.
Flooding caused major disruptions to New York's subway service and the Metro-North commuter rail service, according to the Metropolitan Transportation Agency, which operates both. Some subway lines were suspended entirely, and many stations were closed.
New York Mayor Eric Adams declared a state of emergency for the city.
"This is time for heightened alertness and extreme caution," he said at a morning news conference.
"If you are at work or school, shelter in place for now."
Systems producing intense rainfalls such as Friday's have become more common in many parts of the United States, including the New York City area.
Global warming has produced more extreme weather patterns in many parts of the world, according to climate scientists.
The rain capped one of New York's wettest Septembers on record, with 35cm of rain falling during the month as of Friday, and more on the way. The record was set in September 1882 when 43cm of rain fell.
In some spots the water pooling on the street was 13cm deep, spilling over the tops of her children's rain boots.
Floodwaters marooned vehicles on neighbourhood streets and poured into subway stations, disrupting morning traffic for millions of commuters.
In neighbouring New Jersey, low-lying Hoboken, a city directly across the Hudson River from lower Manhattan, declared a state of emergency, with all but one of the southern routes into town under water.
The city's newly installed floodgates, designed to close automatically when water pooled on roadways, were down, blocking many streets to vehicular traffic.
Friday's deluge followed a bout of heavy downpours and unrelenting winds last weekend from the remnants of Tropical Storm Ophelia. That storm soaked New York City and caused widespread power outages in North Carolina, Virginia, Pennsylvania and New Jersey.
In New York, intermittent rain this week further saturated the ground, setting up conditions conducive to flash flooding.
Australian Associated Press