One such storm is Hurricane Hazel , which struck Toronto in 1954. A tropical cyclone with winds of 64 knots or greater is called a hurricane . A mature hurricane ranges from several hundred to a thousand kilometres across. Tropical cyclones affecting eastern Canada develop over the tropical or subtropical North Atlantic Ocean, Caribbean Sea or Gulf of Mexico. As the storm moves north over land or cooler water it begins to dissipate.
Tropical cyclones tend to follow seasonal tracks.
The early season storms of June and July originate in the Gulf of Mexico and the western Caribbean Sea. These storms rarely affect eastern Canada. Those most likely to affect the Atlantic provinces originate in a broad band from Florida southeast to the Cape Verde Islands during August, September and October. On average, three tropical cyclones per year affect or threaten to affect Atlantic Canada. However, this number can be considerably higher.