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Climate change may be fueling increase in major Northeast snowstorms

Scientists say the recent surge of intense Northeast winter storms is probably tied to rising ocean temperatures and changes in the Arctic

Students sled down the steps of Widener Library in Harvard Yard on Saturday in Boston. (David Degner for The Washington Post)
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Saturday’s tremendous coastal storm pushed a band of heavy snow into southern New England, burying cities under a snowpack up to two feet deep. These near-record snowfall totals continue an astonishing run of historic storms to impact the Northeast in recent years, probably attributed, in part, to anthropogenic climate change.

“Extreme snowstorms, even in the face of longer term declines in winter snow, are entirely consistent with the effects of global warming,” Justin Mankin, a professor at Dartmouth College who studies climate change and variability, said in a statement. “Storms like this are emblematic of the fact that we need to do a better job of managing their risks now to make us more resilient for the future.”

In Boston, where records extend back to 1936, Saturday’s storm tied the all-time calendar day snowfall record, with 23.6 inches accumulating. In recent decades, such extreme snowfall has been unusually common: 15 of the 30 largest single-day snowfalls have occurred since 2000.

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Islip, home to the National Weather Service that covers New York City and surrounding counties, was shy of its record for most snow in a single day by only 0.2 inches. At the Islip station, which has been collecting data since 1963, four of the five largest 24-hour snow events happened since 2010; the fifth was in 2006.

Several major cities in the Northeast, all with record-keeping that extends back many decades, have seen top or near-top single-day snowfall in recent years:

  • Providence, R.I., set its record Saturday
  • Albany, N.Y., saw its third-largest storm in 2020, within 3 inches of the record
  • Binghamton, N.Y., set its record in 2017
  • New York City’s Central Park set its record in 2016
  • Baltimore set its record in 2016
  • Newark saw its second-largest storm in 2016, within 2 inches of the record
  • Virginia’s Dulles Airport saw its second-largest storm in 2016, within 0.2 inches of its record
  • Portland, Maine, saw its second-largest storm in 2015, within 0.1 inches of its record
  • Bridgeport, Conn., set its record in 2013
  • Hartford, Conn., set its record in 2011
  • Philadelphia saw its second-largest storm in 2009, within 4 inches of the record

Single-day records are not the only objective way to quantify the incredible winter weather activity of recent years. A metric known as the Northeast Snow Impact Scale (NESIS), which calculates the population-weighted snowfall footprints of winter storms, can be used to compare the social strain induced by Northeast winters. Analysis of NESIS data shows the 2008-2018 period saw more than three times as many winter storms as any other decade since at least 1958-1968.

Scientists say the recent decadal surge of Northeast winter storms is probably tied to climate change.

One study found a strong relationship between episodes of Arctic warming and severe winter weather events in the Northeast. Warming episodes in the Arctic can destabilize the polar vortex, or a ring of fast winds encircling the upper latitudes of the Northern Hemisphere that keeps the cold Arctic air at bay. When the vortex is pinched, stretched or displaced, it can allow the frigid Arctic air to spill south into the United States.

“When Arctic temperatures are cold, snowfall is less likely [in the Northeast],” wrote Judah Cohen, author of the study and director of seasonal forecasting at Atmospheric and Environmental Research, in an email. “The probability of snowfall increases as the Arctic warms and spikes higher when the Arctic is warmest.”

As the Arctic is warming twice as fast as other parts of the world, Cohen said these polar outbreaks are possibly made more frequent and potentially bringing more winter storms south into the Northeast United States.

While many scientists agree that these polar vortex disruptions are often associated with severe Northeast winter weather, Cohen says that linking anthropogenic climate change to these disruptions, as he has done, is still somewhat contentious.

Arctic climate change may not be making winter jet stream weird after all

Less contentious is the role of ocean warming. Heat content in oceans worldwide has been steadily increasing, with each decade hotter than the last. The Gulf of Maine takes one of the top spots — warming faster than 96 percent of the world’s oceans. In the fall of 2021, water temperatures in the inlet were the highest on record.

“This blizzard was driven by a combination of favorable meteorological conditions and a warmer Atlantic, the latter of which is a signature of global warming and likely intensified the storm above and beyond what it would have been,” Mankin wrote.

As sea surface temperatures warm, the air above becomes hotter. Warmer air allows for more water to enter the vapor phase in the atmosphere, which can feed into winter storms and increase snowfall.

“It may seem counterintuitive to see heavier snowfalls in a warming climate,” Jennifer Francis, acting deputy director of the Woodwell Climate Research Center, wrote in an email. But “with warming also comes increased water vapor in the atmosphere to fuel storms with moisture and energy.”

She said the warming oceans can also help energize the storms responsible for Northeast snow. Because oceans cool much more slowly than land, outbreaks of cold air — perhaps from the Arctic — can induce dramatic temperature gradients from the land to sea. This temperature gradient can set up more hot air-cold air clashes and help strengthen storms.

“Nowhere is this more evident than along the U.S. Atlantic seaboard, where abnormally warm ocean temperatures clash with frigid Arctic air masses, setting the stage for strong nor’easters,” Francis wrote.

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