Up to three feet of snow is expected to fall in parts of the Northeast from Monday evening into Wednesday morning, and as a result, several airlines are preemptively cancelling flights.
Some airlines made the announcement as early as Sunday evening, basing their decision on the expected forecast.
More than 6,368 flights have been canceled for Monday and Tuesday as of 4 p.m. EST Monday, and the snow has not yet started falling.
According to FlightAware, airlines have grounded 2,747 flights Monday and an additional 3,621 on Tuesday. For Wednesday, 245 flights have been grounded at this point.
The effects are expected to last throughout the week, even as weather clears, as a backlog of stranded passengers may need to compete for seats when flight schedules resume.
United Airways planned to cancel all Tuesday flights at Logan International Airport, as well as at airports in New York City, Newark and Philadelphia, according to The Boston Globe.
"We plan to operate a full schedule at our Washington Dulles hub on Monday, but will limit operations beginning Monday evening at our Newark hub, LaGuardia and JFK," United said in a statement on Sunday. "At this point, we plan to cancel all flights Tuesday at Newark, LaGuardia and JFK, as well as Boston and Philadelphia. We are waiving change fees that otherwise may apply, and most customers will find they can change their travel plans most quickly by visiting united.com."
JetBlue canceled 990 flights scheduled through Wednesday morning; Cape Air canceled 28 flights scheduled for Monday; Southwest canceled more than 130. Virgin America canceled 30 flights in Boston and New York on Monday and Tuesday.
Delta Air Lines has grounded about 600 flights for Monday, and US Airways plans to ground flights at certain airports on Tuesday, according to USA Today.
Several carriers have said they're waiving change fees for flights across the region.