Fog advisory issued by Environment Canada
Environment Canada issued a fog advisory for most of Ontario on Christmas Day, warning of reduced visibility and hazardous driving conditions. The advisory covered areas such as Orillia, Barrie, Collingwood, Midland, Toronto, Hamilton, Ottawa, Kingston, and Windsor.
The fog was caused by warm and moist air moving over the cold snow-covered ground, creating a layer of dense mist that reduced visibility to less than 500 metres in some places. The fog was expected to persist until late afternoon or evening, when a cold front would sweep through the province and bring gusty winds and colder temperatures.
Travel plans affected by foggy weather
The foggy weather affected the travel plans of many Ontarians who were celebrating Christmas with their families or friends. Some flights were delayed or cancelled at Toronto Pearson International Airport and other airports in the province due to the low visibility. Drivers were advised to slow down, keep a safe distance from other vehicles, and use low-beam headlights and fog lights.
Some people took to social media to share their experiences of the foggy Christmas Day. Some posted pictures of the eerie scenery, while others joked about the weather being a fitting end to a challenging year.
Foggy Christmas Day not unprecedented
While a foggy Christmas Day may seem unusual, it is not unprecedented in Ontario. According to Environment Canada, the last time a fog advisory was issued for the province on December 25 was in 2015. The weather agency also said that fog is more common in the fall and spring, when there are larger temperature differences between the air and the ground.
Fog is a type of cloud that forms at the surface of the earth, when the air temperature drops below the dew point, or the temperature at which the air becomes saturated with water vapour. Fog can reduce visibility and affect transportation, navigation, and outdoor activities. Fog can also create beautiful and dramatic effects, such as fogbows, halos, and sun dogs.