A large portion of midwestern and southwestern Ontario was blanketed by dense fog on Wednesday morning.
Environment Canada issued a fog advisory for Goderich, Bluewater, and southern Huron County, as well as London, Middlesex County, Elgin County, and Oxford County.
The fog was so thick, visibility in some areas was near zero, the national weather agency warned.
"Visibility may be significantly and suddenly reduced to near zero. Travel is expected to be hazardous due to reduced visibility in some locations," Environment Canada said in its advisory.
The fog slowed the morning commute and led to numerous bus delays and cancellations in Huron-Perth and Wellington County. The full list can be found on our closures page.
Environment Canada expected the fog to lift near midday Wednesday.