By Shivansh Tiwary

Jan 26 (Reuters) - A powerful winter storm sweeping across much of the United States forced airlines to cancel thousands of flights and delayed hundreds on Monday, as freezing rain and heavy snowfall disrupted travel and snarled transportation networks.

Over ‌3,600 flights were canceled and 714 were delayed as of early Monday, according to flight-tracking website ​FlightAware, following more than 11,000 cancellations reported on Sunday.

The number of ‍cancellations and delays was expected to rise as ⁠the day progressed.

Low pressure ⁠south of New England is expected to move east over the Atlantic on Monday, bringing ‌heavy snow to parts of the ​Northeast and freezing rain across sections of the Mid-Atlantic, the U.S. National Weather Service said.

Snow is also expected along ⁠the Appalachian region, while rain will ‍spread along ​the Southeast coast as a cold front moves offshore, the agency said.

American Airlines ( AAL ) accounted for the largest share of disruptions on ‍Monday, with nearly 570 flights canceled and about 57 delayed, followed by Republic Airways, JetBlue Airways ( JBLU ) and Delta Air Lines ( DAL ).

Boston's Logan International Airport, Dallas Fort Worth International Airport and New York's John F. Kennedy International Airport were among the hardest hit.

Major U.S. carriers rolled out sweeping ​travel ‍waivers and flexible re-booking options to assist passengers whose travel plans were disrupted by the cancellations.

Airline operations are highly interconnected, meaning ​cancellations can leave aircraft and crews out of position, complicating efforts to restore normal flight schedules.

The storm also impeded road travel. The Federal Emergency Management Agency warned that driving conditions could become dangerous as blizzard-like conditions, strong winds and ice spread further.

Meanwhile, hundreds of thousands of customers across several U.S. states, from ​Tennessee to the Carolinas, reported power outages, with Tennessee reporting the highest number of cases.

More than 820,000 customers were without electricity as of early hours on Monday, according to ‍data from PowerOutage.us.

(Reporting by Shivansh Tiwary in Bengaluru; Editing by Shinjini Ganguli)