Torrential rain sent water surging through New York's subway system and road tunnels and across airport runways yesterday.
The storm, which also spawned a rare tornado, hit just before dawn, and by rush hour, subway pumping stations became overwhelmed, leaving passengers stranded.
The US National Weather Service said a tropical air mass dumped an extraordinary amount of rain in a short period of time on New York. The worst was recorded between 5am and 8am (10am and 1pm Irish time), with 2.5 inches falling on Central Park and almost 3.5 on Kennedy International Airport.
The subway problems come as weather experts predict New York is due for a major hurricane.
A storm with 130 mph winds and a 30-foot storm surge could cause the Hudson and East rivers to overflow - and bring with it more significant flooding.
AP