In meteorology, the life cycle of a tropical cyclone starts with cloud clusters that develop into a low pressure area (LPA). Once this LPA intensifies, it becomes a tropical cyclone, the general term for “bagyo”. This tropical cyclone is then classified based on its wind speed.
Through the years, the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) has used three official tropical cyclone categories: Tropical Depression, Tropical Storm and Typhoon.
Yolanda, with the international name Haiyan, which made its landfall in the country last November 2013, is remembered as one of the strongest typhoons last year. The Visayas area was largely affected, where storm surges caused massive destruction to lives and properties.
Days before the first anniversary of Yolanda, the Typhoon Committee of PAGASA has decided to revise the classification of tropical cyclones, adding the category “Super Typhoon” on its list. The new tropical cyclone classifications are as follows:
Tropical Depression (TD) has maximum sustained winds of up to 61 kilometers per hour, equivalent to up to 17.1 meters per second and up to 33 nautical miles per hour.
Tropical Storm (TS) packs 62 to 118 kilometers per hour or 17.2 to 32.6 meters per second. If measured in knots, it will reach 34 to 64 miles per hour.
Meanwhile, a Severe Tropical Storm will only be applicable for the International Warning for Shipping, and will not be used for general public dissemination unlike the other categories.
Typhoon (TY) is used in identifying a tropical cyclone with wind speeds 118 to 220 kilometers per hours, equivalent to 32.7 to 61.1 meters per second or 64 to 120 knots.
Super Typhoon (STY) has maximum sustained winds of more than 220 kilometers per hour or more than 61.1 meters per second. STY is as powerful as 120 nautical miles per hour.
PAGASA explained that the revision aims to emphasize the intensity of a tropical cyclone and the threat of its impacts. Using the term “Super Typhoon” will also escalate the sense of urgency and community response in times of an approaching storm.
However, PAGASA Weather Forecaster Samuel Duran stated that the usage of the term Super Typhoon will be effective in 2015.