What did climate change make more likely along the nor’easter’s path?

What did Climate Central measure?

In an analysis published Sept. 24, Climate Central examined unusually warm sea-surface temperatures in the storm’s development area and forecast path. The organization’s Ocean Climate Shift Index estimates how human-caused climate change affects the likelihood of daily ocean temperatures; it is not an event-by-event estimate of storm formation or damage.

Climate Central said waters in the storm’s development area were 81 to 83 degrees Fahrenheit, about 2 to 4.5 degrees above normal. Farther north, it expected the storm to cross waters of 75 to 80 degrees, about 2 to 4 degrees above normal.

The analysis found that human-caused climate change made the unusual temperatures 10 to 50 times more likely, with the likelihood reaching as high as 70 times in some areas along the forecast path. Those multipliers describe the ocean temperatures, not the nor’easter.

Three distinctions keep the finding in perspective:

1. The measured change was ocean heat. The analysis connected human-caused warming to the increased likelihood of unusually warm sea-surface temperatures in the storm’s development area and along its forecast path.
2. The possible effects are pathways, not a storm-specific tally. Climate Central said warmer water can increase evaporation and atmospheric moisture, potentially adding fuel for rain. It also said sea-level rise raises the starting water level for coastal storms, making flooding more likely or severe. The analysis did not quantify how much either pathway changed this storm’s rainfall or flooding.
3. The study did not attribute the storm’s formation or damage. It does not establish that climate change caused the nor’easter, its track, winds, duration, rainfall totals or the flooding communities experienced.

Climate Central also pointed to prolonged onshore winds and repeated high tides as conditions that can add to coastal flooding and erosion. When elevated water levels coincide with high tide, homes, roads and other low-lying places can face repeated exposure even as a storm weakens.

What did the nor’easter bring to communities?

In New Jersey, more than 4 inches of rain had fallen in some locations since Friday, the Associated Press reported. Sea Bright experienced flooding during successive high tides. A resident’s garage filled with about a foot of water, and Caroline Virenius, a Sea Bright resident, told the Associated Press, in a report republished by PBS News, “It's not like a one-time occurrence”.

The flooding extended beyond the Jersey Shore. AP reported water covering streets in Howard Beach, Queens, and tidal flooding in low-lying New Jersey neighborhoods. On Long Island, wind gusts toppled trees, damaged homes and brought down utility poles.

More than 130,000 customers across the Northeast and mid-Atlantic were without power at points on Sunday, according to PowerOutage.us figures cited in AP’s reporting. That was a time-specific count, not a final total for the storm.

The damage included a fatal incident. CBS News reported that Leighton Brown, a 56-year-old New York City Housing Department employee, died after a tree fell on him in Brooklyn. CBS also reported that a swimmer who had been missing was later found alive.

These impacts are not, by themselves, evidence that climate change caused this storm’s rainfall or damage. They do show the range of risks local preparedness must address: water returning with high tides, rain accumulating on land, and wind bringing down trees and utility infrastructure.

What does the longer-term research show?

A 2025 study summarized by the University of Pennsylvania found that nor’easters had become less frequent since 1940, while the strongest storms showed intensifying winds and heavier precipitation. That long-term result provides context for coastal planning; it does not show that climate change caused this storm or its specific impacts, and it does not mean every nor’easter is becoming stronger.

A warming climate can alter conditions that storms encounter without determining whether a particular storm forms. Likewise, a higher sea-level baseline can make coastal flooding more likely or severe without establishing how much of one storm’s floodwater came from sea-level rise. Keeping those distinctions clear helps residents and officials use climate research without turning a finding about warmer water into a claim about a storm’s odds or a precise damage estimate.

The impacts also raise concrete questions about what protections work as flooding recurs. AP reported that Sea Bright had rules adopted after Superstorm Sandy requiring homeowners to elevate houses. Resident Bernard Dowd said those measures likely reduced flooding in his neighborhood, and that he wished he had used sandbags. The available reporting does not establish how widely those protections were used or how their costs and benefits were distributed.

What remains uncertain as the storm weakens?

On Monday, the National Weather Service’s New York office forecast a weakening nor’easter, with additional rain and minor coastal flooding possible around high tide. Its forecast discussion did not confirm that the forecast flooding would occur. Final rainfall totals, outage counts and damage figures were also not established in the reporting available Monday.

The practical task for local officials is to plan for the hazards documented in this storm—repeated coastal flooding, heavy rain and wind damage—while treating climate attribution precisely. The analysis identifies a warming influence on the unusually hot waters; it does not supply a final accounting of the storm’s losses or the climate contribution to them.