Wind Shear; Tornado - INSIGHT STRIKE FINDER Pilot's Manual

STRIKE FINDER

Wind Shear

The effect of wind shear on an aircraft can be devastating, especially in low
level flight such as taking-off or landing. In these stages of flight the
aircraft's performance is severely degraded beyond its capability to
compensate.

Tornado

A Tornado is a swirling column of upward flowing air which is found below
cumulonimbus clouds, (see Figure 38). Wind speeds of up to 180 kts
have been recorded. Tornadoes typically have a diameter of 300 feet to
2,000 feet, although there are reported tornadoes of one mile. They occur
typically on the south to southwest side of severe thunderstorms in the
midwest. In fact, they occur on the water side, the source of energy.
Storms spawning tornadoes must be given the widest avoidance.
Figure 38. Tornado
PILOT'S GUIDE
Wind shear is the sudden "tearing" or "shearing" effect
when there is a violent change of wind over a short
distance. The change can occur in either speed or
direction (horizontal and vertical), or both. Wind shear
occurs when a concentrated, severe downdraft from
within the thunderstorm, known as a downburst, sends
an outward burst of very strong damaging winds
toward the ground.
DIGITAL WEATHER AVOIDANCE
45