O'Hare International Airport tweeted early Thursday that over 470 flights have been canceled due to weather.
Midway International Airport is also canceling over 240 in anticipation of wintery conditions.
As holiday travelers rush to make their flights before the storm takes over, O'Hare officials say double the people are checking in Thursday morning than a normal day. An estimated 4,500 people are making their way through the airport in an hour's time. On an average busy morning, there is about 2,500 people each hour.
Snowfall will begin to ramp up Thursday afternoon, with travel conditions being the worst after dark. Wind gusts will reach as much as 35mph creating whiteouts in open areas.
Lines are long and road traffic is congested outside terminals. If your flight is heading out before the storm, allow for some extra time at the airport.