# Tornadoes

> Aviation perspective on tornadoes, waterspouts, and severe convective weather hazards.

- **Subject:** 050 — Meteorology
- **Section:** 050-09 — Flight Hazards
- **Topic code:** 050-09-05
- **Last reviewed:** 2026-04-01
- **Author:** Pablo Asensio Martínez
- **HTML version:** https://pilotsyllabus.com/en/meteorology/flight-hazards/tornadoes/

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A tornado is a violently rotating column of air extending from the base of a thunderstorm (usually a Cumulonimbus or large Cumulus) to the ground.

![Severe F5 Tornado](https://upload.wikimedia.org/wikipedia/commons/9/98/F5_tornado_Elie_Manitoba_2007.jpg)

## Characteristics
*   **Formation**: Typically associated with severe thunderstorms, especially **supercells**. They require great instability and strong vertical wind shear (warm, moist air at the surface, cold, dry air aloft).
*   **Funnel Cloud**: This is the initial stage, when the vortex descends from the cloud but does not yet touch the ground. It becomes a tornado upon making contact with the surface.
*   **Dimensions**:
    *   Average diameter: Around 100 meters.
    *   Maximum: Can reach 300 meters or more in extreme cases.
*   **Rotation Speed**: Winds around the core can exceed **200 knots**.
*   **Movement Speed**: The tornado moves over the ground at a typical speed of **20 to 40 knots**.
*   **Duration**: Generally short, less than 10 minutes, although they can last up to 30 minutes.
*   **Pressure**: The core of the tornado is an area of **extremely low pressure**.

## Global Occurrence
*   **United States ("Tornado Alley")**: The region with the highest global incidence (average > 1000 tornadoes/year). This is due to the frequent clash between warm tropical air from the Gulf of Mexico and cold polar air from Canada.
*   **Europe**: Tornadoes do occur (approx. 300/year), but they are generally less frequent, of lower intensity, and smaller diameter (100-150 m) than in the USA.
*   **Global**: Can form almost anywhere on Earth if conditions are suitable.

## Related Phenomena
*   **Dust Devil**: A small vortex that forms from the ground upwards due to strong surface heating (thermal). Occurs on hot, dry days, without the need for storm clouds.
*   **Waterspout**: A tornado that occurs over water.

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Free study notes from pilotsyllabus.com. Not a substitute for training at an approved ATO.