CHICAGO (CBS)– Airlines have canceled over 500 Chicago flights after severe thunderstorms in the area.

As of about 9 p.m. Sunday, 635 flights had been canceled at O’Hare International Airport, and 50 flights have been canceled at Midway International Airport.

Average delays at O’Hare were around 47 minutes and 16 minutes at Midway.

Severe storms swept through the area on Sunday morning.