The US weather service lifted storm warnings for the upper midwestern area, most recently affected by the storms, but said the Great Lakes region, bordering Canada, could still be affected by heavy snow.
 
Warnings in Canada
 
The storm swept through Colorado and Wyoming on Friday, then spread snow and ice on Saturday from Texas north to Wisconsin.
 
On Sunday, snow fell across much of Wisconsin and eastern Minnesota and parts of Michigan and Indiana before heading north towards the Great Lakes region.
 
Canada's weather service also issued warnings for communites along the  coastlines of Lake Ontario and Erie.
 
Four people died in and around the city of Montreal over the weekend in weather-related accidents, Canadian television channel CBC reported.