Fog causing airport delays, cancellations

Fog is causing some chaos for travelers on what is traditionally one of the busiest travel days of the year.

Delays of up to 90 minutes and some flight cancellations are being reported by the Chicago Department of Transportation at the two Chicago-area airports Wednesday morning.

As of 7:40 a.m., the Chicago Department of Aviation did not quantify the amount of delays or cancellations, just acknowledged that the fog is causing delays and that travelers should contact their airlines before heading out this morning.

The department of aviation said about 1.8 million passengers are expected to move through the two airports this week. Sunday is expected to be the busiest day, when O'Hare alone could see more than a quarter million travelers.

A dense fog advisory remains in effect for northern and central Illinois, meteorologists from the National Weather Service said.

The advisory is expected to be lifted by 10 a.m. The airports are expected to catch up right after.