Denver is under a dense fog advisory after visibility dropped to below a quarter mile Thursday morning.

At Denver International Airport, nearly 70 flights have been delayed as of 8:30 a.m. Thursday, and five flights have been canceled.

The National Weather Service in Boulder warned morning commuters to be cautious on the road during rush hour and give themselves extra time to stay safe.

The fog is expected to break up later Thursday morning, and the dense fog advisory ends at 10 a.m.

Thursday’s fog also mirrors Wednesday’s fog, when over 300 flights at DIA were delayed throughout the day.