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How can microbursts create dangerous wind shear for airplanes?

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Weather forecasting Doppler radars, such as this one operated by the U.S. National Weather Service at New Underwood, South Dakota, extract the Doppler frequency shift of the echo produced by a moving target by noting how much the frequency of the received signal differs from the frequency of the signal that was transmitted.

A microburst creates dangerous wind shear for airplanes primarily during takeoff and landing by forcing a sudden, unexpected transition from a headwind to a tailwind.12

The Mechanics of the Hazard

Microbursts are intense, localized downdrafts that descend from rain clouds and fan out horizontally upon hitting the ground. Because these events are compact—typically affecting an area only 1 to 3 km in diameter—and short-lived, they can be difficult to detect, especially in arid regions where the associated rain may evaporate before reaching the surface.13

When an aircraft encounters a microburst, the rapid shift in wind velocity and direction disrupts the airflow over the wings. This sudden change in speed and direction forces the pilot to contend with a swift transition from a headwind, which provides lift, to a tailwind, which reduces lift. This loss of lift during critical phases of flight, such as landing or takeoff, has been identified as the cause of several airline crashes. To mitigate these risks, many airports now utilize weather radar systems to detect these intense wind patterns.12