Almost 500 flights have been canceled at Chicago's airports as they continue to clean up following a series of heavy snowfalls in the area.

At Midway Airport, Southwest Airlines announced that they had cancelled all of their remaining flights on Sunday after running low on de-icing fluid for their planes.

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"We have paused our service for the remainde rof the day for the safety of our customers and crews," the airline said in a statement. "We will continue to work with our customers on their travel plans and apologize for any inconvenience the disruption in service has caused."

At O'Hare, where 4.1 inches of snow had fallen on Saturday and Sunday, more than 200 flights had been canceled, according to the Chicago Department of Aviation. A total of 222 flights were canceled, and the average delay on departing flights was around 22 minutes as of 4 p.m. Sunday.

Midway Airport fared worse in the cancellation department, as 265 flights were cancelled at the airport due to the wintry weather. Average flight delays of more than 15 minutes were reported on Sunday afternoon.

The Chicago-area received several waves of snow, including a storm Friday that dumped as much as a foot of snow in western areas. Chicago Public Schools cancelled classes as a result of the snow, and over 1300 flights were cancelled at the area's airports.

On Saturday night and into Sunday morning, even more snow and some sleet fell, prompting a Winter Weather Advisory and hazardous travel conditions in some areas.