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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Canada Scope Weather Desk. Data from Environment and Climate Change Canada and other national met services via Open-Meteo.
A tornado is a violently rotating column of air extending from a thunderstorm to the ground, with wind speeds that can exceed 400 km/h in the strongest events. In Canada, most tornadoes occur between May and September, primarily in the Prairies and southern Ontario, and understanding the conditions that form them is the key to staying safe.
What causes a tornado to form?
Tornadoes develop from severe thunderstorms, usually supercells, when three ingredients combine: warm, moist air near the surface; cooler, dry air aloft; and a strong change in wind speed or direction with height (wind shear). This creates a rotating updraft called a mesocyclone. If the rotation tightens and descends, a funnel cloud forms; when it touches the ground, it becomes a tornado. While a tornado cannot form without a storm, not every severe storm produces one—the specific wind shear and instability must align.
How do you know a tornado is coming, especially at night?
Signs a tornado is coming at night include a sudden, loud roar like a freight train, flashes of lightning that reveal a low, rotating cloud base, and a persistent green or black sky. During the day, look for a visible funnel cloud, large hail, or a wall cloud. A weather warning from Environment and Climate Change Canada is the most reliable alert; a tornado warning means a tornado has been sighted or indicated by radar. If you are searching for a “tornado near me,” check the latest Canada weather warnings immediately.
Can there be a tornado without a storm?
No. A tornado is always attached to a thunderstorm, usually a supercell. However, not every thunderstorm produces a tornado—the storm must have the right rotation and updraft strength. For current conditions, check Canada’s weather hub for updates on weather storms tornadoes today.
What is the difference between a tornado watch and a tornado warning?
A tornado watch means conditions are favourable for tornadoes to develop; stay alert. A tornado warning means a tornado has been sighted or indicated by radar—take shelter immediately. Warnings are issued by Environment and Climate Change Canada.
What are 3 causes of a tornado?
The three main causes are: warm, humid air near the ground; cooler, dry air aloft; and strong wind shear that creates rotation. These ingredients combine in a severe thunderstorm to form a mesocyclone, which can tighten into a tornado.
How fast can a tornado’s wind speed reach in km/h?
Most tornadoes in Canada are EF0 to EF2, with wind speeds from 90 to 220 km/h. The strongest (EF5) can exceed 400 km/h, but these are extremely rare in Canada. The Enhanced Fujita scale rates damage, not direct wind measurement.