CHICAGO (CBS)–  The FAA has lifted the Ground Stop at O’Hare and Midway airports, but many  flights will still be impacted.

Planes were grounded just before 6:45 a.m. Tuesday until 8 a.m.

There is a Dense Fog advisory in effect in the Chicago area.

Officials are advising travelers to check with their airlines for flight information.

As of 11:15 a.m., over 70 flights have been canceled at Midway Airport and average delays over 15 minutes. minutes.

At O’Hare Airport, 65 flights have been canceled, but average delays are over 30 minutes.

MORE NEWS: Brown Cloud In Lake Michigan Shuts Down Beaches At Indiana Dunes National Park

This is a developing story.