New York City received several inches of rain within hours across all five boroughs, as did suburban New Jersey Friday, knocking out several subway and commuter rail lines, stranding drivers on highways, flooding basements and closing a terminal at LaGuardia Airport for hours.As residents faced the quick flooding tied to the remnants of Tropical Storm Ophelia, it was enough for Gov. Kathy Hochul to declare a state of emergency. And she had a particular warning to residents who live in basements.
Some 8.65 inches of rain had fallen at John F. Kennedy Airport by nightfall Friday, surpassing the record for any September day set during Hurricane Donna in 1960, the National Weather Service said. Plus, this summer, the early arrival of an anticipated El Niño ocean weather phenomenon is adding to heat and other weather extremes, which can mean more water in places.Earlier this summer, dangerous flash floods were responsible for at least six deaths in Bucks County, Pa. Pennsylvania flooding followed similarly dangerous conditions in New York and Vermont earlier in July. China, India and other parts of the globe have been dealing with their own flooding extremes.
One of the biggest differences between flash floods and generalized flooding is that flash floods can be more dangerous than people think. Even a few inches of water can have a current that knocks people down and just a few feet of water can send a car floating. Flash flooding at night is particularly dangerous, because unknown depths are disguised, looking simply like wet surfaces.