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A car rocked like flotsam in thigh-deep water in Brooklyn. A cascade ran down subway stairs in Harlem while a nonchalant commuter checked her phone. The rain knocked out power for some 200,000 New Jersey customers, a day after a heat wave caused tens of thousands to suffer blackouts in New York City.
The chaos came not from a “superstorm,” but an intense, short thundershower.
A day later, on Tuesday, officials and residents across the region sounded an alarm: If summer weather swings create this level of havoc, they said, the New York area is not ready for the sharper extremes that climate change will bring — let alone the next hurricane.
“Every data point suggests that climate change is moving a lot quicker than city government,” Scott M. Stringer, the city’s comptroller, said in an interview. “We did not have a superstorm last night. We had rainfall, and people were literally swimming on Carroll Street,” he added, referring to flooding in Brooklyn. “If that is not a clarion call for focus, then I don’t know what is.”
Some New Yorkers on Monday took matters into their own hands. On the flooded Long Island Expressway, Daphnee Youree, 50, waded out of her car in Crocs and pulled debris from a clogged grate with a traffic cone, draining the pool.
After Hurricane Sandy, which devastated swaths of New York City and coastal New Jersey in 2012, the federal government allocated $14.7 billion to help the city rebuild and make its infrastructure more resilient — measures that included building sea barriers, hardening subway stations and flood-proofing boilers and wiring in homes. But only 54 percent of the allocated money has been spent, Mr. Stringer’s office reported last May.
Climate scientists warn that as Earth heats, the region can expect more frequent heavy rainstorms, 100-degree temperatures, high-tide flooding and intense storms, which could inundate Lower Manhattan, wipe out coastal neighborhoods and overwhelm infrastructure.
Those threats have spawned resiliency plans and proposals priced at billions of dollars that are far from being implemented; while they are hashed out, stopgap measures, like walls of sandbags and concrete, are being used to protect areas such as Wall Street and Red Hook.
Climate change drove the passage last month of an ambitious New York State law that requires nothing short of reshaping the economy to eliminate carbon emissions.
But even as urgent action is needed to address those grandiose challenges for the coming decades, the double whammy of climate change and aging infrastructure is hitting now. Just 10 days ago, a burning 13,000-volt cable touched off another power failure, on Manhattan’s West Side.
And floods that are smaller but far more frequent than the catastrophic ones brought on by Sandy are already overwhelming sewers, sluicing pollution into waterways and damaging neighborhoods, said Costa Constantinides, the chairman of the City Council’s Committee on Environmental Protection.
“It shows that we have a long way to go as a city,” he said of Monday’s floods and the weekend blackouts that resulted from heavy air-conditioner use, which he said would only get worse as temperatures rise.
“We’re going to see not just the big floods, not just storm surge, but flooding a little bit more in communities every time there’s rain,” he said. “We need to come up with a five-borough resiliency plan — it’s not just Lower Manhattan, but every corner of New York City.”
The Council last year required that the city map vulnerable areas and make plans to address flooding there. Experts have asked Congress to do the same for the whole country.
Innovative measures are being called for, like building green roofs and porous surfaces; taxing properties that generate excess runoff; or issuing special bonds to finance green infrastructure. But at the same time, officials say, old-school infrastructure maintenance and sewer improvements can make a difference immediately.
In Mr. Constantinides’s district, in Astoria, Shore Boulevard had flooded knee-deep in recent storms because its drainage outlet, which led directly into the adjacent East River, was blocked by sand and stones. After a recent cleaning, the area had only minor flooding on Monday.
But in other areas, officials struggle to pinpoint fixes. The lack of quick answers on the cause of flooding on Monday on Beard Street in low-lying Red Hook “bodes poorly for our preparedness,” said the local City Council member, Carlos Menchaca.
More than two inches of rain had fallen in Central Park by 8 a.m. on Tuesday, the National Weather Service said. More than three inches of precipitation were measured in parts of Queens, Staten Island, Long Island and New Jersey.
Winds, and in some cases, hail, left more than 300,000 customers without power in New Jersey. More than 88,000 were still without service on Tuesday afternoon.
In New York, as heat turned to downpour on Monday evening, some commuters wrapped plastic bags around their shoes to protect their feet before fording newly formed rivers. Others simply shrugged and waded into water.
“It was crazy,” said Ms. Youree, the driver who was brought to a standstill on the Long Island Expressway. “I’d never seen anything like that on the L.I.E.”
Drivers waited to see if the water would clear.
“Everybody was just standing around,” she said in an interview on Tuesday. “So, I decided to just do it.”
She left her 11-year-old son and her cat in the car.
As she worked to clear the mud and wood, ultimately removing three grates, she said people cheered her on. A video of her digging away the muck was posted on Twitter, where she was applauded by the Council speaker, Corey Johnson, as a “Great New Yorker.”
Ms. Youree laughed off the praise: “I just wanted to get home,” she said.
Michael Gold contributed reporting.