downburst(redirected from Macroburst)
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Related to Macroburst: downburst
A local high-velocity downward movement of air mass flowing out of a thunderstorm. It is the chief cause of severe wind shear. The size of a downburst may vary from a ¼ mile to more than 10 miles. It can last from 5 to 30 minutes. The wind speed can go as high as 120 knots. It is potentially very dangerous, especially during the takeoff and landing phases.