DOWNBURSTS Meaning and
Definition
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Downbursts are powerful and abrupt downdrafts of air that descend from a thunderstorm or other convective cloud, reaching the ground in a concentrated area. These intense vertical air currents are characterized by a rapid and excessive downward flow of air, often rotating and creating significant wind shear. Downbursts can be classified into two main types: microbursts and macrobursts.
Microbursts are smaller in scale and typically cover an area less than 4 km in diameter. They are usually short-lived, lasting around 5-15 minutes. Although they may be less intense than macrobursts, they can still pose a significant threat to aviation, as the rapid change in wind direction and speed can cause aircraft to lose control, especially during takeoff or landing.
Macrobursts, on the other hand, are larger in size and cover an area greater than 4 km wide. They can persist for longer durations, reaching up to an hour. Macrobursts unleash tremendous amounts of wind energy, capable of generating winds over 160 km/h. Their violent downward motion of air can cause significant damage to structures and vegetation, similar to that of a tornado or a hurricane.
Both microbursts and macrobursts are associated with severe weather events, often accompanied by intense rainfall, hail, and lightning. They are usually the result of convective processes within towering cumulonimbus clouds, triggered by strong updrafts. Understanding downbursts is crucial for meteorologists, pilots, and emergency management officials to forecast and respond effectively to potential hazards, while helping to enhance safety measures for individuals and infrastructure in affected areas.
Etymology of DOWNBURSTS
The word "downbursts" is a combination of two separate words: "down" and "bursts".
The word "down" originates from Old English and has been used to mean "lower in position" or "toward or in a lower place" since the 13th century. It can also indicate a downward direction or movement.
The word "bursts" is derived from the Old English verb "berstan", which means "break or shatter violently". Over time, "berstan" turned into "bresten" in Middle English and later evolved into "burst" as we know it today.
When these two words are combined, "downbursts" refers to atmospheric phenomena characterized by a strong and swiftly moving downward flow of air, usually associated with thunderstorms or intense convective activity.
