Wind shear is a hazard to aviation because it cause turbulence and airspeed fluctuations. As a pilot, you should be particularly aware of wind shear on take-offs and landings. Since we can't see the wind, we have to keep an eye on potential causes of wind shear. The animations below in provide visuals of the potential of wind shear and turbulence.

Wind shear is best described as a change in wind direction and/or speed over a short distance in the atmosphere. Wind shear can be a danger to flying. It can generate turbulence near the surface. As you descend through vertical wind shear during a landing you should be aware of the possibility of turbuluence andyour head winds, which can increase or decrease depending on the orientation of the shear with your flight line.

During departure under conditions of low-level wind speed, a sudden decrease in head-wind will cause a loss in airspeed equal to the decrease in wind velocity.

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Sometimes local runways are nearby to buildings, which can generate turbulence, as in the above example.

Below, a line of trees can cause turbulence and wind shear that can be a hazard during take-off and landing.

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We've already discussed the danger of downdrafts from storms on landing and takeoffs. A row of clouds, or cloud streets, also give you an idea of the wind below the clouds - both the horizontal and vertical winds (as demonstrated below).

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