A microburst can be characterized by a downdraft of which rate?

• A. 500-1000 fpm
• B. 2,000-3,000 fpm
• C. 3,000-6,000 fpm
• D. 7,000-9,000 fpm

Answer: (C)

A microburst is a garden-variety, high-velocity downdraft inside a thunderstorm that reaches the ground and spreads out, creating strong surface winds and wind shear. The important detail is how fast that air accelerates downward. In most cases, the downdraft velocity falls in the range of a few thousand feet per minute, with 3,000 to 6,000 fpm capturing the typical strength seen in these events. This range reflects the level of vertical speed that produces the rapid, damaging winds pilots must contend with on approach or departure. Speeds around 500–1,000 fpm are too modest to be characteristic of a microburst, while 2,000–3,000 fpm is possible but doesn’t reflect the higher end commonly emphasized in training; speeds of 7,000–9,000 fpm are rare outliers rather than the standard expectation. Therefore, the downdraft rate is best described as 3,000–6,000 fpm.