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WIND SHEAR




Wind shear is very dangerous to any aircraft and can occur at any altitude. It can rapidly change the performance of the aircraft and disrupt the normal flight attitude. Low-level wind shear is especially hazardous due to the proximity of an aircraft to the ground.


Wind shear

Wind shear is a sudden change in wind speed and or wind direction at any altitude. It can affect aircraft with strong updrafts or down drafts, and horizontally across the aircraft.


Low-Level Wind Shear

Low-Level Wind Shear (LLWS) is very dangerous due to the close due to how close an aircraft is to the ground. This type of wind shear is common with passing frontal systems, thunderstorms, temperature inversions, and strong upper-level winds greater than 25 knots.


  • Temperature inversion - When a temperature inversion is present low-level wind shear will often occur before sunrise. A brief, light to mod turbulence is possible where underlying cold air meets warm air above. This typically erodes after sunrise.



Microbursts are another type of low-level wind shear and are the most severe. An indication of a microburst is an intense rain shaft at the surface. Virga at the cloud base and blowing dust is the only visible clue. Virga is rain that falls but evaporates prior to striking the ground.

  • Microbursts have a horizontal diameter of 1 – 2 miles, with a depth of 1,000 feet.

  • Microbursts lifespan can last anywhere between 5 – 15 minutes.

  • Downdrafts up to 6,000 feet per minute, along with headwind loss of 30-90 knots.

Virga rain



Remember wind shear is undetected and a silent danger to aircraft at any altitude and time. Be alert when flying around thunderstorms and frontal systems.


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