“The typhoon came out of the sea first as a deep hollow roar. I was surrounded by the madness, the unreason, of uncontrolled, undisciplined energy. None of this made any sense. It was worse than useless – it was nature destroying its own creation – its own self. To create by the long process of growth and then to destroy by a fit of wild emotion – was this not madness, was this not unreason?”—Pearl S. Buck
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As I write this column, the Philippines is still under the mercy of Kristine, the 11th typhoon to hit the country this year. Another typhoon may hit the country soon and its name is Leon.
The names of the rest of the typhoons this year are Marce, Nika, Ofel, Pepito, Querubin, Romina, Siony, Tonyo, Upang, Vicky, Warren, Yoyong, and Zosimo. And if all those names are used even before the year ends, there are 10 back-up names: Alakdan, Baldo, Clara, Dencio, Estong, Felipe, Gomer, Heling, Ismael and Julio.
“There is no month in the Philippines which is free from typhoons,” says the Philippine Atmospheric, Geophysical and Astronomical Service Administration (PAGASA), which issues weather advisories for tropical cyclones.
Each year, about 20 tropical cyclones enter our country. Fortunately, only 6 to 9 of these tropical cyclones make landfall.
A typhoon is a mature tropical cyclone that develops in the northwestern part of the Pacific Ocean. In the eastern Pacific Ocean, identical phenomena are called hurricanes but when these tropical cyclones move into the western Pacific they are designated as typhoons.
Within the northwestern Pacific there are no official typhoon seasons as tropical cyclones form throughout the year. “On average, the northwestern Pacific features the most numerous and intense tropical cyclones globally,” reports Chris Landsea of the US National Hurricane Center.
“Nearly one-third of the world’s tropical cyclones form within the western Pacific,” wrote James B. Elsner and Kam-Biu Liu in a paper which appeared in Climate Research. “This makes this basin the most active on Earth.”
Scientific studies have shown that Pacific typhoons have formed year round, with peak months from August to October. The peak months correspond to that of the Atlantic hurricane seasons.
Like any tropical cyclone, there are six main requirements for typhoon formation and development: sufficiently warm sea surface temperatures, atmospheric instability, high humidity in the lower to middle levels of the troposphere, enough Coriolis force to develop a low pressure center, a pre-existing low level focus or disturbance, and low vertical wind shear.
Meteorologists – those who study interdisciplinary scientific study of the atmosphere – say that while these conditions are necessary for tropical cyclone formation, they do not guarantee that a tropical cyclone will form.
Depending on the intensity and strength of the winds that they bring, tropical cyclones are classified as tropical depression, tropical storm, severe tropical storm, and typhoon. (For trivia fanatics: “Bagyo,” a Filipino word which means typhoon, arose after a 1911 storm in the city of Baguio had a record rainfall of 46 inches within a 24-hour period.)
A tropical depression has maximum winds of up to 63 kilometers per hour (kph). A storm has winds moving anywhere from 64 kph to 87 kph. It is considered a severe storm when the winds move between 87 kph and 118 kph. When it exceeds 118 kph, a typhoon ensues, according to PAGASA.
The movement of a full-fledged typhoon is closely watched by weathermen through radar and satellite images. The eye of the typhoon is used as a reference point on the location of the typhoon.
Before 1890, tropical cyclones were given arbitrary names. Clement Wragge, an Australian weatherman, began naming tropical cyclones after ladies prior to the end of the 19th century. Male names were given to those that originated in other places.
“Normally, Wragge was said to bestow this honor among politicians who had incurred his disfavor,” PAGASA said. In 1947, forecasters decided to identify using names in alphabetical order. Military communicators suggested female names for those forming in the northern hemisphere, and male names for those in the southern half.
Three agencies have given names to tropical storms in the northwest Pacific Ocean since 1963, which frequently leads to a cyclone having several names. Tropical cyclones were given names by the US Navy’s Joint Typhoon Warning Centre from 1945 until 2000, when the Japan Meteorological Agency (JMA) took control. Tropical cyclones that developed into tropical storms were given names by both organizations.
Only in 1963 did the country’s weather agency start giving local names to tropical cyclones that move within its jurisdiction, even if they already had an international name previously.
In order to identify all tropical cyclones that occurred inside the Philippine Area of Responsibility, PAGASA first chose four sets of Filipino women’s nicknames that ended in “ng,” numbered A through Y. The Pilipino alphabet was used to construct and arrange the four groups of names.
Names for each set are used for each year so that the groups will be repeated every four years. In cases when all names have been used and typhoons are still coming, the weather bureau has contingencies. It has auxiliary names up to 10, starting from letter A to letter J.
The weather bureau brushed aside existing knowledge that typhoons are named after females in the past because of the tendency of women and typhoons to both change their minds in a very short span of time.
“It’s not true because a typhoon changes like a woman’s mind that typhoons were given a female name in the past,” a PAGASA official clarified.
