Patterns in Frequency, Intensity and Geography of Tropical Cyclones in the Philippines: An Ex Post Facto Analysis for Disaster Risk Reduction

Abstract

This paper aims to analyze patterns in frequency, intensity and geographic landfalls of the various tropical cyclones recorded in the Philippines since the early 1960’s. The study made of use of the descriptive ex post facto design through analysis of historical records of major typhoons that hit the Philippines since 1960. Data were obtained from the freely-accessible information posted by PAG-ASA, the weather bureau of the Department of Science and Technology, on the internet. Results revealed that while there is substantial statistical evidence that major destructive typhoons are more often occurring in recent years than in the previous 5 decades in the Philippines, we find no indication that the intensities are getting stronger. The major typhoon intensities are still governed by some random mechanism whose probability distribution can be described as a mixture distribution. It is more probable for the more recent major  typhoons to have maximum sustained winds exceeding 150 kph. Property damage and casualties are not correlated with typhoon intensities but are more probably more closely associated with the amount of rainfall and the consequent severe flooding and landslides triggered by the severe weather disturbance. Finally, there are two (2) major geographical “hotspots” noted in the analysis, namely, the western sea board of  Luzon (Southern Luzon and the Bicol region) and Southern Philippines (Eastern Visayas and Northeastern Mindanao) which will be most frequently visited by these major natural disasters in the future.