Tornadoes
Tornado: violently rotating air column in contact with ground, under a cumuliform cloud (AWH 22.7.9).
- Winds inside can exceed 200 kt.
- Very low pressure in vortex.
Vortex names (by what it touches):
| Name | The vortex |
|---|---|
| Funnel cloud | does not reach the surface |
| Tornado | touches land |
| Waterspout | touches water |
Visibility:
- Funnel often visible, not always. Otherwise debris at the surface shows ground circulation (AWH 22.7.9).
- Vortex extends well into the cloud: pilot on instruments in a severe storm could meet one (AWH 22.7.9).
- Any cloud connected to a severe thunderstorm may hold one (AWH 22.7.9, PHAK ch.12).
Occurrence:
- Occur in both isolated and squall-line thunderstorms (AWH 22.7.9).
- Families of tornadoes can trail as appendages several miles out from the main lightning and precipitation area (AWH 22.7.9, PHAK ch.12).
Entering vortex: almost certain loss of control and structural damage (AWH 22.7.9).
Trap: judging safety by funnel visibility; vortex can hide in cloud or show only as ground debris.
References
- FAA-H-8083-28_aviation-weather-handbook.md 22.7.9 (Tornado)
- FAA-H-8083-25_PHAK ch.12 (Tornadoes)