Tuesday , May 22, 2018

Sanchez: Dangers: Twisters

THE only thing missing is Dorothy Gale. And Negros Occidental could as well be Kansas. I remember Dorothy being swept away by a tornado to the Land of Oz.

Dorothy is fictional, but tornadoes in Kansas are not. In fact, the central part of the United States gets many tornadoes, particularly strong and violent ones, because of the unique geography of North America.

The combination of the Gulf of Mexico to the south and the Rocky Mountains to the west provides ideal environmental conditions for the development of tornadoes more often there than any other place on earth.

SunStar Bacolod recently reported that 19 Negrenses were injured while 49 houses were hit as tornadoes struck seven villages in Bacolod City and Negros Occidental last week.

I Googled back issues of SunStar. I was struck with the frequency of twisters hitting the province. Last year, a tornado struck Barangay Magballo, Kabankalan City.

In 2014, a tornado damaged 100 houses and left one injured in a barangay in Isabela town. The year before, a twister struck Barangay Mambulac, Silay City.

Storms that produce strong tornadoes are also most likely to occur when the horizontal winds in the environment increase in speed and change with increasing altitude.

Philippine Atmospheric, Geophysical and Astronomical Service Administration senior weather specialist Jun Galang noted that it is the frequency of severe thunderstorms that could cause tornadoes.

These thunderstorms are also brought in by the monsoon winds from the southwest side of the Philippines, typical occurrences during this period of the year.

Galang stressed that even with severe thunderstorms, the formation of tornadoes is not always guaranteed.

And oh yes, the usual suspect. Climate change is instrumental in causing tornadoes. Can we expect more to come along with floods and storm surges?

Typically, tornadoes are formed when warm moisture above land meets with cold, dry air above it. As the warm air pushes upwards (called an updraft), the wind changes direction from horizontal to vertical, gradually creating a vortex.

The stronger the updraft of warm air, the stronger the rotation of the vortex becomes, thus creating what is called a “mesocyclone.” This eventually becomes the tornado.

The Philippines is prone to various climate/weather-related hazards because of its location in the tropics, along the path of typhoons, monsoons and El Niño-La Niña. We might add tornadoes.