Nor'easters are getting stronger. What does that mean for Long Island's future?

Common sense and some climate models suggest that a warming planet will get less snow.

Tell that to a Long Islander who just experienced one of the strongest blizzards on record in a winter that has dropped 59.5 inches of snow and counting on the National Weather Service observation station at Islip’s MacArthur Airport, about 3 feet more than average.

But some powerful winter storms might be occurring because of, not in spite of, warming trends, experts said, a phenomenon that would be costly and dangerous for Long Island and the rest of the Eastern Seaboard.

From the 20th century into the 21st, these storms have done billions of dollars in snow, wind and coastal flooding damage to communities from Washington, D.C. to Boston. They are called nor’easters because their winds are typically from the northeast. The storm that just swept over Long Island, bringing hurricane-force winds and a possible (not yet official) record 31 inches of snow in Central Islip, was one.

"The strongest nor’easters are getting stronger," University of Pennsylvania researchers wrote in a 2025 paper published in Proceedings of the National Academy of Sciences. Analyzing 900 nor’easters that occurred from 1940 through 2025, they found that for the most intense storms — stronger than 99% of the total — peak wind speed increased from 69 mph to 74 mph, or just over 7%.

"That might seem a modest increase, but power dissipation by a storm varies as the wind speed cubed, so that increase in peak wind speeds corresponds to a sizable, roughly 20% increase in destructive potential," climate scientist Michael E. Mann, one of the paper’s authors, wrote in a 2025 blog post. Hourly precipitation rates also increased.

Nor’easters are a type of extratropical cyclone. That family of storms, so named because they form outside of the tropics, is the source of much of our severe winter weather. Those systems feed on temperature differentials between subtropical and subarctic air masses. A warming planet, with warming amplified at the poles, should therefore yield weaker extratropical cyclones, Mann wrote in an email, because "this temperature contrast is projected to decrease over time." 

But nor’easters are a special case, Mann continued. "What makes nor’easters (Atlantic coastal ETCs) unique is that a share of their energy is derived from the warmth of the oceans and, specifically, the heat given off by the evaporation of ocean water. They have this in common with hurricanes. And just as the stronger hurricanes are getting stronger, the strongest nor’easters appear to be getting stronger too."

As Mann wrote in his 2025 blog post, "Those nor’easters that do develop have the potential to grow stronger than they otherwise would have in the presence of unusually warm ocean waters."

Are major, if sporadic, winter storms becoming a feature of life on Long Island?

The New York State Climate Impacts Assessment, released in 2024, predicts a future with fewer very cold days and significantly wetter winters, with more precipitation falling as rain than snow as temperatures rise. 

Winter precipitation on Long Island is projected to increase between 5% and 18% by the 2050s and between 11% and 28% by the 2080s, according to the assessment. Annual precipitation is also projected to rise, but less drastically.

Snowfall data from Islip suggest that some change could already be underway on Long Island. Compared to the early years of data collection at the National Weather Service's observation station, which started in 1963, there are now fewer snowy days in a typical year, and on days when it does snow, snowfall tends to be significantly heavier, according to a Newsday analysis of data from the National Oceanic and Atmospheric Administration's National Centers for Environmental Information. Of the 24 single and multiday snowfalls of 12 inches or more recorded at Islip since the start of data collection, 16 occurred after 2000.

From 1963 through 1973, it snowed on Long Island about 10 days per year; over the last decade, it snowed only about six days per year. On average, a snowy day in the 1960s meant about 2.7 inches of snow; by the last decade, that rose to 4.9 inches. (The analysis treated consecutive day snowfalls as single snowfall events.)   

A cluster of snowfall events could be a function of "natural climate variations, but there could also be a contribution from human impacts," Jase Bernhardt, an associate professor of sustainability and atmospheric science at Hofstra University, said in a phone interview. "A warmer atmosphere can hold more water vapor," which could lead to wetter winter storms, he said. 

Anthony J. Broccoli, director of the graduate program in atmospheric science in the Department of Environmental Sciences at Rutgers University, said in a phone interview that snowfall data are "notoriously challenging to work with" because factors like wind can skew results.

But overall, he said, "as the climate warms, it’s going to be less likely to get snow instead of rain during the winter. That doesn’t mean, when we do get a snowstorm, that it won’t be a big one, because the machinery is still there to produce a big snowstorm. ... If you get the right combination of a storm with a lot of moisture and temperatures cold enough for snow, it can mean a huge dump."