Third Assignment

Tornado and Windstorm : Twin Sons from Thunderstorm

We have witnessed for some windstorms in Indonesia that has damaged many things around. In these months, we have watched some news reporting about ‘puting beliung’ that occurred in some places across the country. The last windstorm hit Yogyakarta was in February 2009. Although windstorm causes many damages and injures people, the information about windstorm provided by the government is very rare. The main cause is that windstorm or tornado is not predictable in a long time before the occurrence. Even in the United States, tornado is never predicted long time before it happens.

Windstorm in Indonesia is similar to tornado in North America. The difference is the quantity and quality of occurrence. In North America, tornadoes happen many times in spring. Five tornadoes could happen a day in a same region. The quality is also able to be ranked from EF0 to EF5 in Enhanced Fujita Scale. Different in Indonesia, due to the archipelago, Indonesia receives less tornado or windstorm in wet. The quality is also never as big as in North America.

A tornado is born from a thunderstorm and usually accompanied by dark cloud, lightning and rain. The process of its birth is started by a cold wind which blows fast on the high altitude. A great and wide plain has more possibility as the birthplace of a tornado compared to the rugged place because the high wind flows freely. While the cold wind blows free in the high altitude, a hot breeze flows slowly in the land’s surface. Those winds meet up and causes horizontal whirlwind. A thunderstorm has a deep effect of their meeting. During the storm, the whirlwind is being erected by the surface hot wind which flows upward and be a vertical whirlwind. Then mesocyclone is formed by the mixing of the rotated wind which is erected by the surface wind. It then makes the thunderstorm to live long after stabilize the thunderstorm. After that, cooler air moves downward on the backside of the storm to the ground. The birth process ends, and a new tornado is born.

On its short life, tornado moves directed by the thunderstorm. When a tornado is formed on the mesocyclone, it’d move straight. It’s also affected by the thunderstorm’s velocity, when it moves fast; the path would be straight as arrow. But when it moves slowly; the path would be identified as loops. For a tornado which is formed outside the mesocyclone, it’d move fast and happen quickly; then followed by another tornado. The material sucked by tornado depends on the land’s surface. When a tornado crosses a town, the material would be the house’s roof, paper, barks, leaves and even cars. When tornado happens in the lake, water would be sucked by it.

Until now, the destiny of a tornado is still debated by scientists. Tornado happens in a short time and cannot be predictable. That what have made scientists cannot learn much about tornado. But at least, when we see a thunderstorm forms mesocyclone, it’d be better to stay at home in the basement or under the table.

source:

Fortin, Jacques, et. al. Visual Ilmu Pengetahuan Populer untuk Pelajar dan Umum: Memahami Iklim dan Lingkungan. Jakarta: PT Bhuana Ilmu Populer. 2006.

Shapiro, Alan. "Tornado". Microsoft® Encarta® 2009 [DVD]. Redmond, WA: Microsoft Corporation. 2009.