Habitation Fog

FTLComm - Tisdale - Monday, January 28, 2002

Throughout the Arctic region when the temperature drops to -40º the warm gases from heating, vehicles and even respiration freeze in the air. Weathermen often refer to this as "ice fog" but the correct term is "habitation fog" From Russia to Canada's Arctic this form of fog is a frequent visitor during the winter and in some places it is particularly dangerous. The city of Whitehorse rests in a slot between two sets of mountains and the area in which people live is on several stages of plateau. One of these, Porter Creek is the lowest and wood burning

fireplaces and stoves are popular. With typical -40 weather and colder the air is trapped in between the mountains and the exhaust gases are trapped under the heavy cold air and form a toxic barrier over the community. Here in Tisdale there was little wind during the night and the exhaust from furnaces built up the fog seen in the pictures before dawn and just afterward but once the sun was up the air was warm up to -28º and the fog quickly disappeared. Unlike other forms of fog habitation fog is not water suspended in the air but is accurately described by weathermen as ice fog as the tiny particles are ice crystals and does not form hoar frost on trees and fences. Whitehorse is not the only Canadian city to suffer from the affects of habitation fog, with low winds Edmonton and Winnipeg when hit with -40º can develop very thick air, so much so to make driving hazzarous. However, the prairie cities of Regina, Saskatoon and Winnipeg rarely have calm enough air to see this form of fog for more than a very short while simply because the air movement around these settlements will cause the fog to dissipate quickly.