According to Flight Aware’s cancellation listing, major airlines—namely Southwest (LUV), American (AAL), and JetBlue—have axed the most flights for March 14. As of Monday afternoon, Southwest has scrapped 884 flights, and American Airlines has canceled 619. JetBlue trails American at the third most, at 616. But with more than 18 inches of snow expected in some areas, there’s a good chance those numbers could rise dramatically.

Airports in the New Jersey, New York, Boston, and Baltimore-Washington D.C. have canceled the majority of flights for Tuesday. But as of Monday, Chicago O’hare took the biggest hit: According to the listing, more than 200 flights there were halted on March 13.

Though flight cancellations are a pain, there is some good news—most airlines are offering free rebooking for those affected by the storm. To see what you should do if your flight was canceled, check out our list below:

Southwest: Without incurring an additional fee, affected customers can rebook or travel standby within 14 days of their original travel date.

JetBlue: Customers traveling to or from cities affected by the storm can rebook their flights from March 13 to March 16. They can also choose to refund trips booked before March 10.

American Airlines: Depending on the airport, passengers traveling to or from affected cities can change their flights to March 15 or March 17 without a fee.

United: Travelers flying through affected cities can rebook through March 17 without paying a change fee.

Spirit: Customers can rebook through March 16 or March 18, depending on the airport.

Delta: Those who are slated to fly March 14 or March 15 can rebook travel through March 17 without a fee.

Frontier: Those traveling between March 13 and March 15 can reschedule through April 7 without an additional charge.