Tornado Alley
It has also been asserted that there are numerous Tornado Alleys. In addition to the Texas/Oklahoma/Kansas core, such areas include the Upper Midwest, the lower Ohio Valley, the Tennessee Valley and the lower Mississippi valley. Some studies suggest that there are also smaller tornado alleys located across the United States.
Tornado Alley
Another third of Canadian tornadoes strike Southern Ontario, especially in the region halfway between the Great Lakes from Lake St. Clair to Ottawa. This happens because tornadoes in this region are triggered or augmented by lake breeze fronts from Lake Huron, Lake Erie, Lake Ontario, and Georgian Bay. Tornadoes do not often hit lake shadow regions, although they are not unknown, and some, such as the 2011 Goderich, Ontario tornado, have been violent. However, most Ontario tornadoes are concentrated in a narrow corridor from Windsor and Sarnia through London, and then northeast to Barrie and Ottawa. Tornadoes up to EF4 in strength have been documented in this region.