Bad weather forced Dallas-based Southwest Airlines to cancel numerous flights over the weekend, according to the airline.

According to a report on NBC 5 News, planners from the airline giant anticipated operational challenges on Sunday as the winter weather that hit North Texas on Saturday afternoon moved towards the Eastern Seaboard.

As of 9 a.m. Sunday, Southwest had already canceled around 400 of the day’s flights, with the airline’s representatives saying they are working to accommodate customers affected by the cancellation. The representatives also added they anticipate more cancellations to follow.

Passengers at airports who were affected by the storm dealt with challenges brought on by the extreme weather, according to the Dallas-based airline operator.

According to NBC 5 News, the wintery weather conditions caused 490 cancellations on Saturday, with most of them primarily centered in the Midwest.