A massive winter storm is expected to hit New England and Texas, so airlines cancelled hundreds of flights ahead of it.

According to FlightAware, more than 1300 U.S. flight cancellations were reported on Wednesday. More than 1,600 flights were cancelled on Thursday.

Heavy freezing rain from Texas and the Ohio River Valley, as well as snow throughout the Midwest is what the National Weather Service predicted. Winter weather warnings were issued by federal forecasters for parts of New England and Texas.

Southwest AirlinesFlightAware reports that it cancelled nearly 400 Wednesday flights or 12% of the schedule. It also cancelled 517 Thursday flights or 15%, which is 15% less than its scheduled flight. The airline suspended all flights to its Dallas Love Field hub on Thursday. American AirlinesThere were more than 350 cancellations of mainline flights for Wednesday.

American and Southwest Airlines DeltaAnd UnitedThey also announced that they will waive any fare differentials for passengers who are rebooking flights due to the storm.

Due to a second storm hitting the Northeast, more than 4,000 U.S. airlines cancelled flights last week. To avoid crews and passengers getting stuck at airports due to severe weather, airlines cancel most flights before large storms. This makes it much easier for them to restart the flight the next day.