• Travel plans were disrupted nationwide. More than 2,000 flights had been canceled across the country on Wednesday morning, many at airports in the storm’s path, according to FlightAware. More than 200 others had been delayed. Amtrak modified service in the region and the Metro-North Railroad announced a reduced schedule for Wednesday.
• Thousands of people were already without power. FirstEnergy, a utility company, reported a combined 48,000 customers without service in Pennsylvania and New Jersey.
• Do you have a question about the causes of dangerous winter storms? Ask John Schwartz, a New York Times reporter who covers climate change and the environment, for an answer by emailing firstname.lastname@example.org. Here are some answers so far.
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Warnings and alerts are in place from Maryland to Maine.
Snow was already falling Wednesday morning across much of Pennsylvania and New Jersey, and winter storm warnings and weather advisories were in effect from Northern Maryland to Maine, as well as in parts of the Appalachians in West Virginia.
But meteorologists were unable to pin down exactly where and when rain would turn into snow.
The National Weather Service forecast two to five inches in Baltimore, four to six inches in Philadelphia, and just one to two in Boston, with the storm expected to track farther west than some earlier forecasts had indicated.
Coastal flooding was possible in New England, and heavy, wet snowflakes were expected to place power lines in peril.
Hundreds of thousands were still without power from last week’s storm.
The storm came just a few days after heavy snow and high winds assaulted the region on Friday, which knocked out power for 2.7 million.
Around 240,000 were still without power on Tuesday, according to the United States Energy Department. (The department said that it expected everyone to have power back by the end of the day, but that full restoration might be affected by Wednesday’s bad weather.)
Gov. Andrew M. Cuomo of New York said in a briefing on Tuesday that 78,000 people were still without power in the state, which he considered “unacceptable.”
“These storms have now become the rule rather than the exception, and they have to have the capacity to quickly restore power,” he said.
Is there some connection between climate change and this cold weather?
Scientists have been looking at phenomena like cold spells, which occur when air from the Arctic dips south. After all, the Arctic is warming as a result of climate change, and that appears to be weakening the jet stream, which tends to hold that cold air up toward the top of the world.
As Marlene Kretschmer, a researcher at the Potsdam Institute for Climate Impact Research in Germany, told The Times in January, the connection is not yet fully established. “There’s a lot of agreement that the Arctic plays a role, it’s just not known exactly how much,” she said. “It’s a very complex system.”
Read more answers to common questions about winter storms.
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