
Observations Tell Us What Is Actually Happening In A Storm. They Are The Key To Understanding How Tornadoes Form.

Big whirls have little whirls, that feed on their velocity; and little whirls have lesser whirls and so on to viscosity….Lewis Fry Richardson 1922
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For Specific Tornado Types
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At the high-end of the damage scale (EF4 to EF5), violent tornadoes form in extremely well-organized supercells. These powerful tornadoes are often long-track, can be wide and account for most of the lives lost.

Mid-range tornadoes (EF2 to EF3) most often form in supercells, but can also develop in bow echoes, quasi-linear convective systems, or in hurricanes. Their parent storms are less organized than their violent counterparts.

— Ted Fujita