A major New Year’s snowstorm barreled across the Midwest Thursday and into the densely populated Northeast Corridor, carrying with it enough of a punch to blanket areas from New York to Boston with more than a foot of snow.

“During Thursday and Thursday night, the storm will affect 20 states with more than 120 million people in the Midwest and the Northeast combined, and could have a major negative impact on travel for people returning from holiday destinations, heading back to school or resuming business activities,” Alex Sosnowski, senior meteorologist at Accuweather, noted Thursday afternoon.

Sosnowski said that it would be far from the worst blizzard to ever hit the area, “but people should be prepared for flight delays and cancellations because of direct and indirect impacts from the far-reaching storm.”

Winter storm warnings and weather advisories stretched from Illinois to Georgia and up the Eastern Seaboard to Maine. While the worst of the storm is expected to be over by Friday morning, meteorologists said lingering winds and icy roads could muck up travel well into the evening.

Blizzard conditions and wind gusts as high as 50 mph were pounding some spots Thursday afternoon, with several Massachusetts towns witnessing snow falling at a rate of two inches per hour. Over in New York, Governor Andrew Cuomo announced a statewide state of emergency Thursday, urging residents to stay off the roads.

Many highways in New York like I-84, I-87 South and the Long Island Expressway will close from midnight until 5 a.m. Friday morning. Authorities elsewhere told drivers to expect low visibility and hazardous conditions on major roadways like I-90 and I-95.

AAA estimated that 94.5 million Americans would journey 50 miles or more away from home for the year-end holiday season. More than 90 percent traveled by car, and many were expected to return home Thursday and Friday.

Flight Cancellations And Airline Change Policies

The powerful winter snowstorm had canceled more than 2,100 flights within, into or out of the United States by Thursday evening, according to Houston-based airline tracking service FlightAware. Regional carrier ExpressJet, which operates through capacity purchase agreements as American Eagle, Delta Connection and United Express, reported the most cancellations, with 425 flights nixed from its schedule. American Eagle (325), Southwest Airlines (240), United Airlines (196) and Chautauqua Airlines (149) all showed more than one hundred cancellations due to the storm.

Thursday’s disruptions hit passengers flying out of Chicago O’Hare, Newark Liberty, Cleveland-Hopkins and Philadelphia the hardest. Airlines slashed another 840 flights scheduled for Friday, and those cancellations will also affect passengers flying out of Boston Logan and New York’s John F. Kennedy and LaGuardia airports.

As it has become an industry standard with most major storms, U.S. carriers are offering waivers that allow customers headed into and out of affected airports to change flights free of charge.

U.S. Airways issued a travel advisory that covers 21 airports from Pennsylvania to Maine. Passengers scheduled to travel on Jan. 2 or Jan. 3 can make one fee-free change for dates through Jan. 8.

The winter weather also prompted American Airlines to offer fee-free changes on flights into or out of 11 airports from Harrisburg, Pa., to Boston. Travelers can fly instead on any date through Jan. 8.

Delta Air Lines will allow fliers headed into or out of airports in eight Northeastern states to reschedule flights at no charge for travel on or before Jan. 8. Changes to origins and destinations, however, may result in an increase in fare to include any difference in price between the original ticket and new ticket.

Passengers scheduled to fly home from their year-end vacation on United Airlines through Jan. 5 can also rebook free of charge if departing from or arriving to one of nearly two-dozen airports from Washington, D.C., to Portland, Maine. Customers must complete their final travel by the end of the ticket’s validity.

JetBlue announced that it would waive change fees due to the inclement weather for flights Thursday and Friday into and out of 17 airports from Washington, D.C. to Buffalo. Customers must rebook for travel through Jan. 9 prior to the departure of their originally scheduled flight.

Spirit Airlines initiated a “weather buster policy” for Atlantic City, Boston, New York, Latrobe, Niagara Falls and Philadelphia that allows customers holding reservations for travel to, from or through affected airports to change their reservations without fear of penalty for flights through Jan. 10.

Southwest Airlines also issued a travel advisory for the winter storm, though the 17 affected airports all have separate policies for fee-free changes.

All major carriers said Thursday that they would offer refunds to those whose flights are canceled outright or delayed significantly. They also advised travelers to check their respective websites and local weather forecasts before making the trip to the airport.