CALGARY – Environment Canada issued a fog advisory for Calgary on Tuesday morning.

The advisory was issued at around 6 a.m. MST with a warning that a stretch of fog was present from just south of Red Deer to Calgary, and eastward along Highway 1.

The fog reduced visibility to near zero in some areas.

"Fog isn't reducing visibility everywhere, but there are some thick patches that will persist over the next hour," Meteorologist Jordan Witzel said.

"If visibility is reduced while driving, turn on your lights and maintain a safe following distance," the advisory warned. "If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop."

For more details on the advisories, visit Environment Canada's website.