The occurrence of a column of air perpendicular to the ground with acceleration toward the ground defines a _________.

• A. tornado
• B. gust front
• C. downdraft
• D. microburst

Answer: (D)

A microburst is a localized, intense downdraft that reaches the ground and spreads outward in all directions. The description of air moving straight downward toward the ground and accelerating fits this phenomenon, and what makes it a microburst is the combination of the strong, focused descent with surface winds generated when that air hits the ground and outflows horizontally. A downdraft by itself is any sinking motion, but microbursts specify the small, powerful ground-reaching portion that produces damaging winds in a confined area. The other options don’t match: tornado involves rotation, a gust front is the leading edge of outflow rather than the strong ground-reaching core, and a downdraft alone doesn’t necessarily imply the intense, surface-reaching outflow characteristic of a microburst.