If you’re planning to fly this week ahead of the holiday, you may find your air travel arrangements disrupted by Winter Storm Gail . Airlines have already begun issuing broad travel waivers for passengers who hope to get around the storm by flying earlier, later or canceling altogether.

AccuWeather called the developing nor’easter a "blockbuster storm", forecast to be the most significant the East Coast has seen in years. Its anticipated areas of impact stretch from Maine all the way down to Virginia and North Carolina.

Gail is predicted to drop more snow than all of last winters’ storms in Washington, D.C., Philadelphia, New York City and Boston combined. The Weather Service’s snowfall forecast for Washington, D.C., is three to four inches; for Philadelphia, eight to 12 inches; for New York City, 14 inches; and for Boston, 8 to 12 inches.

But, it’s predicted that the heaviest snowfall will land on western Maryland and south-central Pennsylvania, which may see as much as 2 feet of snow combined with gusty winds, causing near-blizzard conditions from late Wednesday into Thursday morning.

According to USA Today , each air carrier determines which travel dates and destinations its waivers cover, and the fine-print terms will also differ according to airline. These will likely be adjusted in the coming days to adapt to changes in the storm’s projected path and severity.

Customers with non-refundable tickets won’t be eligible for refunds unless the airline itself cancels their flight. But travelers (even those with basic economy tickets) can elect to cancel their trip and be issued a future flight credit for the amount paid for their ticket, and won’t get stuck with any nasty change fees when rebooking.

Ticket-holders needing to change their flights this week should do so sharpish, given that flight options are already limited due to pandemic-prompted cuts and plenty of passengers will be scrambling to alter their plans this week.

Here is a summary of major airlines’ current waiver conditions:

American Airlines

Travel Dates: December 16-17

Traveling To/From: 37 destinations, including such major cities as Baltimore, Cincinnati, Cleveland, New York, Pittsburgh and Washington, D.C.

Delta Air Lines

Travel Dates: December 16-17

Traveling To/From: 19 destinations, including Baltimore, Boston, New York, Philadelphia and Syracuse.

JetBlue Airways

Travel Dates: December 16-17

Traveling To/From: 10 destinations, including Baltimore, Boston, Hartford and New York.

Southwest Airlines

Travel Dates: December 16-17

Traveling To/From: 12 destinations, including Baltimore, Boston, Philadelphia and Washington, D.C.

Spirit Airlines

Travel Dates: December 16-17

Traveling To/From: 12 destinations, including Hartford, Connecticut; New York LaGuardia; Newark, New Jersey; and Akron, Ohio.

United Airlines

Travel Dates: December 16-17

Traveling To/From: 21 destinations, including Albany, New York; Allentown, Pennsylvania; Baltimore; Boston; and New York.