Lake-effect Snow - Great Lakes Region, Ontario Canada

Great Lakes Region, Ontario Canada

Because Southwestern Ontario is surrounded by water on three sides, many parts of Southwestern and Central Ontario get a large part of their winter snow from lake-effect snow. This region is notorious for the whiteouts which can suddenly reduce highway visibility on Canada's busiest highway (Ontario Highway 401) from clear to zero. The region most commonly affected spans from Port Stanley in the west, Brantford and the Bruce Peninsula in the north, Niagara-on-the-Lake to the east, and Fort Erie to the south. The heaviest accumulations usually happen in the Bruce Peninsula, which is between Lake Huron and Georgian Bay. So long as the Great Lakes are not frozen over, the only time the Bruce Peninsula does not get lake-effect snow is when the wind is directly from the south.

Toronto and Hamilton are usually spared lake-effect squalls because they are not on the leeward side of their respective lakes during the dominant northwest winds. However, some central and northern portions of the Greater Toronto Area can be affected a few times each year by lake-effect snow from Georgian Bay. Downtown Toronto and Hamilton get most of their lake-effect snow when the wind comes from the southeast or east, over Lake Ontario. Such easterly winds are usually associated with a winter cyclone passing just to the south of the Great Lakes.

When the wind is from the north, the snowbelt runs north-south from Grand Bend to Sarnia and London. Areas such as Lucan and Arkona have experienced some of the heaviest snowsqualls from Lake Huron in this region. When the wind is slightly more westerly, the snowbelt runs from Tobermory, Owen Sound, and Grand Bend to as far south and east as Arthur, Orangeville and Caledon. This snowbelt often reaches Kitchener and can affect the Halton and Peel regions of the Greater Toronto Area. These northwesterly winds usually also bring snow southeast of Georgian Bay, which can reach beyond Lake Scugog. A westerly wind sends lake-effect streamers east from Owen Sound to Gravenhurst, Barrie, and Orillia, and may even reach as far south and east as York Region in the Greater Toronto Area. When the wind is from the southwest, lake-effect streamers from Lake Huron and Georgian Bay run from Noelville to Sudbury, Gravenhurst, and Algonquin Provincial Park. Some snow bands can occasionally reach Quebec and Maine, while snow originating from Lake Erie, Lake Ontario and even Lake Michigan can impact southern Ontario. Easterly winds primarily affect the Niagara Peninsula. Local lake-effect snowsqualls can occasionally occur downwind of Lake Simcoe when the lake is unfrozen, usually in early winter or late fall.

Lake Superior has its own independent snowbelts, affecting Wawa, Sault Ste. Marie, Marathon, the Keweenaw Peninsula in Upper Michigan, and Pukaskwa National Park. Thunder Bay is usually not affected by lake-effect snow, unless it is associated with a winter storm.