Which statement best describes a microburst?

• A. A strong downdraft with a small horizontal scale
• B. A widespread steady wind
• C. A moderate updraft
• D. A calm air parcel

Answer: (A)

A microburst is a powerful, localized downdraft with a very small horizontal extent. The air inside a thunderstorm can rapidly accelerate downward as it cools and becomes denser, and when this air hits the ground it spreads outward in all directions, creating strong, gusty winds and rapid changes in wind speed and direction over a short distance. This combination—a vigorous downward motion confined to a small area—is why the best description is a strong downdraft with a small horizontal scale. The other statements don’t fit: a widespread steady wind is not localized, a moderate updraft is the opposite vertical motion, and calm air wouldn’t produce the intense surface winds associated with a microburst.