The December 2005 North American ice storm was a damaging winter storm that produced extensive ice damage in a large portion of the Southern United States from December 14–16, 2005, while extensive snowfall was reported across portions of the Canadian provinces of Ontario and Quebec.
The storm was triggered by a deep low pressure system formed over the Gulf of Mexico on 14 December 2005, which began moving northward.
At the same time, cold arctic air from northern Canada penetrated deep into the central United States and lowered the temperatures at the surface while warm air from the Gulf Stream remained at the coast.
The precipitation remained as rain in the coastal areas, including the large cities from Boston to Washington, D.C.
[3][4] In Ottawa, between 20 and 35 centimetres fell in a short period of time causing several OC Transpo buses to become stuck on the city's transitway and several of their articulated buses to become jackknifed at a busy intersection in the suburb of Gatineau, Quebec.