Explained: How strong air currents form within thunderstorms and why they’re harmful
Have you ever observed a small, localised column of sinking air within a thunderstorm? It is quite possible that it is a microburst. Microbursts are strong and powerful air currents that move in a downward direction trapped within a thunderstorm. They can be either wet or dry. During summer, the Southeast countries experience wet microbursts, along with large amounts of rainfall. On the other hand, dry microbursts come along with little or no rain. Do they pose a threat to your health? Yes, microbursts can seriously harm the environment and, in some instances, even endanger life. Let us learn more about these Microbursts!
How are microbursts formed?
As you already know, microbursts usually occur within a thunderstorm. Thunderstorms have strong updrafts which are strong air currents that move upwards. These updrafts suspend water droplets and hailstones within them due to a strong upward current. But as the water droplets and hailstones move upward, they tend to cool down and condense. The condensed water droplets often weaken the updraft that’s carrying it. When the updraft is no longer strong enough to hold the water droplets up, it sinks toward the ground. This is how the core of the thunderstorm plummets to the ground in a strong downward force, creating microbursts.
Are they dangerous?
Yes, microbursts can be pretty dangerous! According to the Enhanced Fujita Scale, microbursts can have wind speeds of 100 mph or even more, comparable to an EF-1 tornado (which can drive a moving car off the road!). Winds this strong can uproot trees and cause significant damage to homes and buildings. It is crucial to treat severe thunderstorm warnings with the same respect as tornado warnings! Why? Because thunderstorms provide the perfect setting for a microburst.
Discovery of microbursts
The microburst phenomenon was first explained by Tetsuya ‘Ted’ Fujita, a Japanese-American meteorologist best known for developing the Fujita scale for assessing tornado intensity. Dr Fujita blamed a powerful gust of wind for a mid-1970 incident where a commercial aeroplane crashed while landing in a rainstorm! His theory was based on earlier aerial observations that revealed a starburst pattern of destruction (spreading from a central point) after thunderstorms had swept through an area. As a result, airports are now extremely watchful for microbursts when thunderstorms are nearby!
Predicting a microburst
There is currently no way to predict where microbursts will occur because of its rapid and small-scale formation. But we can detect them if the weather radar is close enough! In many cases, the conditions that produce severe thunderstorms might also increase the chances of microburst occurrence.
Usually, microbursts form when conditions such as instability, high precipitable water, dry air in the mid-levels and strong winds in the dry layer meet. In the Southeast countries, hot, humid afternoons are the ideal conditions for microbursts.