Intense Tropical Cyclone Occurrences in Mindanao (Philippines)

In the Philippines, an archipelago of 7,100 islands in the western North Pacific, tropical cyclone (TC) activity is high (about 19 annually) but most of these systems propagate towards the northern regions of the country. However, in certain occasions, TCs do develop into tropical storm or typhoon category (> 17ms-1) and propagate towards Mindanao in the southern Philippines, an economically important region. Moreover, there are even rarer intense TCs that neglect the perceived effects of the coriolis parameter and develop within 6˚N and affect areas much closer to the equator. Because of its rarity, these systems cause an unprecedented level of destruction and casualty in Mindanao brought about by severe flooding, landslides and storm surges. In this study, TCs that propagate towards the Mindanao region of the Philippines, which will be called MCT in this paper, were examined. A 68-yr database of MCT occurrences was constructed using the best track data available from Japan Meteorological Agency (JMA), the Joint Typhoon Warning Centre (JTWC) and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). Twenty-nine MCTs that have occurred between 1945 and 2012 were characterised in terms of TC category, manner of propagation, landfall characteristics, origin (position when tropical storm or typhoon intensity was reached) and TC genesis area. The temporal pattern of these events in relation to the characteristics mentioned, including possible relationship to certain climatic variability (e.g. ENSO), were also investigated. This initial investigation of low-latitude propagating intense tropical cyclones intends to gain some insight in climate variability and change in the Philippines in the context of disaster management.