What is the defining feature of a microburst?

A microburst is characterized primarily by an intense downdraft that occurs within a thunderstorm, which then spreads outward upon reaching the surface. This phenomenon is particularly dangerous for aviation due to the sudden and severe changes in wind direction and speed it can produce.

The intense downdraft can reach speeds of over 100 miles per hour and can extend for a short distance, typically less than 4 kilometers (2.5 miles), with the surface winds rapidly dispersing in all directions. This dramatic shift in wind patterns can lead to hazardous flying conditions, making the understanding of microbursts essential for pilots and meteorologists.

The other options mentioned lack the key characteristics that define a microburst. Continuous rain and low thunder, while common to many thunderstorms, do not specifically pinpoint a microburst, as they can occur in various forms of storm activity. Strong winds at high altitudes refer to broader wind patterns and do not capture the localized nature of a microburst. Similarly, while rapid growth of cumulus clouds can indicate storm development, it does not define the specific downdraft behavior that distinguishes microbursts from other weather phenomena.