How Tornadoes Form — Nature's Most Violent Storms

What Is a Tornado?

A tornado is a violently rotating column of air extending from a thunderstorm to the ground. Wind speeds can exceed 480 km/h in the strongest tornadoes, making them the most intense atmospheric phenomenon on Earth.

How They Form

Most significant tornadoes are born from supercell thunderstorms — massive rotating storms with a persistent updraft called a mesocyclone.

1. Wind shear creates horizontal rotation in the lower atmosphere
2. A strong updraft tilts this rotation vertical
3. The rotating column tightens and accelerates (like a spinning ice skater pulling in their arms)
4. A funnel cloud descends; when it touches the ground, it becomes a tornado

The Enhanced Fujita Scale

Tornado Alley

The central United States (Texas to South Dakota) sees the most tornadoes globally, due to the collision of warm Gulf air with cold Canadian air and dry Rocky Mountain air. But tornadoes can occur anywhere, including Bangladesh, Argentina, and parts of Europe.

Safety

• Move to the lowest interior room (basement or interior bathroom)
• Cover yourself with a mattress or heavy blankets
• Stay away from windows
• If in a car, drive at right angles to the tornado's path — do not try to outrun it

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