Ida Floods New York Area

In the aftermath of a ferocious storm caused by the remnants of Hurricane Ida that killed more than three dozen people in four states, national and local leaders acknowledged Thursday that extreme weather events posed an urgent and ongoing threat.

The storm killed at least 43 people in New York, New Jersey, Pennsylvania and Connecticut and left more than 150,000 homes without power. States of emergency remained in effect across the region by midday Thursday, as officials sought to get a handle on the damage.

Speaking from the White House, President Biden said the damage indicated that “extreme storms and the climate crisis are here,” constituting what he called “one of the great challenges of our time.”

At a news conference in Queens on Thursday morning, Gov. Kathy C. Hochul of New York said she had received a call from Mr. Biden, who she said “offered any assistance” as the state assessed the damage from Ida, a storm that she said represented a new normal.

“We need to foresee these in advance, and be prepared,” she said.

The deluge of rain on Wednesday — more than half a foot fell in just a few hours — turned streets and subway platforms into rivers. Emergency responders in boats rescued people from the rooftops of cars. Hundreds of people were evacuated from trains and subways. A tornado in southern New Jersey leveled a stretch of houses. A preliminary report by the National Weather Service determined that the tornado that hit Mullica Hill, N.J., was an F-3 in strength with estimated winds of 150 miles per hour. Some rivers in New Jersey and Pennsylvania were still rising.

The rain broke records set just 11 days before by Tropical Storm Henri, underscoring warnings from climate scientists of a new normal on a warmed planet: Hotter air holds more water and allows storms to gather strength more quickly and grow ever larger.

Many of New York City’s subway lines remained suspended into the evening on Thursday. Airports were open but hundreds of flights had been canceled.

In New York City, the dead ranged in age from a 2-year-old boy to an 86-year-old woman, the police said. Some drowned in basement apartments in Queens, where a system of makeshift and mostly illegally converted living spaces has sprung up.

On Thursday afternoon, Gov. Philip D. Murphy of New Jersey announced that at least 23 people in the state had died. They included four people found dead in an apartment complex in Elizabeth and two people were killed in Hillsborough, N.J. after they became trapped in their vehicles, a spokeswoman for the town said. Another death occurred in Passaic, N.J., where the Passaic River breached its banks and fish flopped in the streets.

Gov. Ned Lamont of Connecticut announced that the state would lower flags to half-staff to honor Brian Mohl, a state police sergeant whose car was swept away by the floodwaters.

The 3.15 inches of rain that fell in Central Park in one hour on Wednesday eclipsed the record-breaking one-hour rainfall of 1.94 inches on Aug. 21. The National Weather Service, struggling to depict the level of danger, declared a flash flood emergency in New York City for the first time.

In Bergen County, New Jersey’s most populous county, County Executive James Tedesco, a former firefighter, said on Thursday: “We have not complete devastation but close to it. This is as bad as I’ve ever seen it.”

Reporting was contributed by Anne Barnard, Jonah E. Bromwich, Maria Cramer, Isabella Grullón Paz, Matthew Haag, Jesus Jiménez, Michael Levenson, Eduardo Medina, Andy Newman, Azi Paybarah, Derrick Bryson Taylor, Neil Vigdor Ali Watkins and Ashley Wong.