The number of tropical cyclones that affect Canada is higher than many people realize, but the majority arrive having already transitioned away from their hurricane status. While a direct landfall by a storm at Category 1 strength or higher is a relatively rare event, the country frequently experiences significant impacts from storms of tropical origin. Understanding how these systems change as they move north is key to grasping the true risk they pose to Canadian landmass and waters.
Defining a Canadian Hurricane Impact
A hurricane is a tropical cyclone, a warm-core storm that draws power from the heat of warm ocean waters. To maintain classification, a storm must sustain winds of at least 119 kilometers per hour and retain its tropical structure, including a symmetric core and an absence of weather fronts. As tropical cyclones move northward into cooler Canadian waters, they typically undergo extratropical transition. This process causes the storm to lose its tropical characteristics, transforming into a cold-core, non-tropical low-pressure system.
The Canadian Hurricane Centre (CHC) refers to this system as a Post-Tropical Cyclone. This designation signifies a change in the storm’s energy source, which now relies on the contrast between warm and cold air masses, similar to a winter storm. The post-tropical classification does not mean the storm is weaker; the wind field often expands significantly, and the storm can still maintain hurricane-force winds. The resulting post-tropical system often carries heavy rain that can lead to catastrophic inland flooding, an equally dangerous threat compared to the wind damage of a pure hurricane.
Frequency and Geographic Distribution
Since modern record-keeping began, over 240 storms of tropical origin have significantly affected Canadian territory or offshore waters. On average, Canada experiences the effects of one or two tropical or post-tropical storms each year. The Canadian Hurricane Centre estimates that roughly every other year, a storm of at least minimal hurricane strength makes landfall or comes close to the Atlantic coast.
The geographical distribution of these impacts is heavily skewed toward the Atlantic provinces due to their proximity to the main North Atlantic hurricane track. Nova Scotia, Newfoundland and Labrador, and New Brunswick are the most frequently affected regions, facing threats from high winds, storm surge, and torrential rainfall. Quebec is also regularly impacted by inland storm remnants, which bring heavy precipitation that can cause flash flooding far from the coast. In contrast, the Pacific coast of Canada rarely experiences tropical cyclone impacts, as the cool waters of the eastern Pacific Ocean prevent storms from maintaining hurricane strength before reaching British Columbia.
Profiles of Noteworthy Storms
One of the most consequential storms in Canadian history was Hurricane Hazel in October 1954, which struck Southern Ontario after tracking north from the Caribbean. Although it had become a post-tropical storm, Hazel’s remnants merged with a cold front, unleashing unprecedented rainfall of over 200 millimeters in the Greater Toronto Area. This massive flooding caused the deaths of 81 people, primarily due to floodwaters sweeping away homes along the Humber River.
A more recent example of a direct, high-wind impact was Hurricane Juan in September 2003, which accelerated and made landfall near Halifax, Nova Scotia, as a Category 2 hurricane. Juan maintained its intensity longer than expected due to the warm waters of the Gulf Stream, producing sustained winds of 158 kilometers per hour. The storm caused widespread destruction in the Halifax Regional Municipality, downing a large portion of the tree canopy and resulting in $200 million in damages.
More recently, Hurricane Fiona in September 2022 became the costliest storm of its kind in Atlantic Canadian history, with insured losses estimated at over $800 million. Fiona made landfall as a powerful post-tropical cyclone, setting a national record for the lowest barometric pressure ever recorded for a Canadian storm. The system brought Category 2-force winds and a devastating storm surge across Nova Scotia, Prince Edward Island, and Newfoundland, causing extensive coastal erosion and infrastructure damage.