Dense fog leading to delays at O'Hare, Midway

Dense fog is causing problems for motorists throughout the Chicago area.

The National Weather Service said a dense fog advisory remains in effect until 10 a.m. and that visibility is less than one-quarter mile.

Motorists are urged to slow down, use headlights and leave plenty of distance ahead to protect against unseen dangers.

The fog is delaying the arrival of some planes at O'Hare, which is causing departing flights to be delayed. The FAA is asking people check with their airline to determine how flights are affected.

Nearly 50 flights have been canceled at Midway Airport.