By Henrylito D. Tacio
“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,” says Rene Paciente, chief of PAGASA’s weather forecasting and warming system. 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 eastern Pacific Ocean, identical phenomena are called hurricanes but when these tropical cyclones move into the western Pacific they are re-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 severe storm when the winds move between 87 kph and 118 kph. When it exceeds 118 kph, 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.
If the typhoon is within the range of the radar, the meteorologists won’t have much problem in monitoring the typhoon. “The radar is more accurate because you see the eye of the typhoon more clearly,” explains Paciente. “With a satellite, which covers half of the globe and gives a full disc picture, the eye is sometimes covered by clouds. It is hard to tell where a typhoon is if you can’t see the eye.”
So far, the author had experienced only one strong typhoon in his life. That was in the 1970s yet when Titang (international name: Kate) hit Mindanao and Western Visayas. Although the reported damage was only P50 million, the typhoon killed 681 people with 284 others missing.
Before 1890, the world’s tropical cyclones were named arbitrarily. A typhoon which devastated Samar and Leyte on October 12, 1897 was called El Baguio de Samar y Leyte. Before the end of the 19th century, an Australian weatherman, Clement Wragge, started the practice of naming tropical cyclones after females. Those which formed elsewhere were given male names.
“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 southern half.
Since 1963, there have been three agencies who have named tropical cyclones within the north western Pacific Ocean which has often resulted in a cyclone having two names. From 1945 to 2000 the US Navy’s Joint Typhoon Warning Center assigned names to tropical cyclones before the Japan Meteorological Agency (JMA), took over the naming of tropical cyclones in 2000. Both agencies assigned names to tropical cyclones when they intensified into a tropical storm.
It wasn’t until in 1963 that the country’s weather bureau started assigning local names to a tropical cyclone that enter the country’s area of responsibility even if the cyclone has had an international name assigned to it.
In the beginning, PAGASA adopted four sets of Filipino women’s nickname ending in “ng” from A to Y to name all tropical cyclones occurring within the country’s area of responsibility. The four groups of names were prepared and arranged according to the Pilipino alphabet.
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. “We have auxiliary names up to 10, starting from letter A to letter J,” says Venus Valdemoro, PAGASA’s information officer.
So far, as of this writing, only two typhoons had entered the Philippines this year: “Amang” and “Betty.”
The other names of typhoons this year are Chedeng, Dodong, Egay, Falcon, Goring, Hanna, Ineng, Jenny, Kabayan, Lando, Marilyn, Nonoy, Onyok, Perla, Quiel, Ramo , Sarah, Tisoy, Ursula, Viring, Weng, Yoyoy, and Zigzag. The auxiliary names are Abe, Berto, Charo, Dado, Estoy, Felion, Gening, Herman, Irma, and Jaime.
For 2016, the names of typhoons are Ambo, Butchoy, Carina, Dindo, Enteng, Ferdie, Gener, Helen, Igme, Julian, Karen, Lawin, Marce, Nina, Ofel, Pepito, Quinta, Rolly, Siony, Tonyo, Ulysses, Vicky, Warren, Yoyong, and Zosimo. The additional names are Alakdan, Baldo, Clara, Dencio, Estong, Felipe, Gardo, Heling, Ismael, and Julio.
The lists of the names of typhoons, however, has been revised several times (in 1979, 1985, 2001 and 2005) for various reasons including to help minimize confusion in the historical records and to remove the names that might have negative associations with real persons.
Names of typhoons that were destructive, resulting in at least P1 billion in damages or have cuased at least 300 deaths, are decommissioned. Titang, for instance, has already been delisted from the tropical cyclone names. Other names which have been omitted from the list include: Dading (1964), Welming (1967), Pitang, Sening, and Yoling (all in 1970), Wening (1974), Didang (1976), Atang and Kading (1978), Nitang and Undang (1984), Herming and Sisang (1987), Unsang and Yoning (1988), Ruping (1990), Uring (1991), and Rosing (1995).
At the start of the 2000s, the following names have been decommissioned: Loleng (2002), Harurot (2003), Unding, Violeta and Winnie (2004), Milenyo (2006), Cosme and Frank (2008), Ondoy and Pepeng (2009), and Juan and Katring (2010).
In recent years, more names have been taken from the list: five in 2011 (Bebeng, Juaning, Mina, Pedring and Sendong), one in 2012 (Pablo), three in 2013 (Labuyo, Santi and Yolanda), and five in 2014 (Glenda, Jose, Mario, Ruby and Seniang).
According to Valdemoro, the weather bureau’s Weather Forecasting Section is responsible in assigning names for tropical storm that were decommissioned. However, names of prominent politicians and celebrities can’t be used “as these may cause public ridicule.” Filipino terminologies and phrases that are offensive to public decency are also not allowed.
Unlike in the olden times, the names of typhoons these days are not exclusively derived from people but also include names of flowers, animals, and foods. Agila and Bagwis, for instance, are names of birds.
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.
“Hindi totoong dahil pabago-bago ang isip ng bagyo tulad ng isang babae kung bakit binigyan sila ng pangalang babae,” a PAGASA official maintained.
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