Although tropical cyclones are rare to southern Africa, Jennifer Fitchett, a Senior Lecturer in Physical Geography at the University of the Witwatersrand, believes that this may not last for long. Results indicate warmer waters along the east coast of South Africa leading to more conducive conditions for these natural disasters to occur. The increase in the frequency of occurrence of intense cyclones may pose a heightened risk of storm damage for countries neighbouring the Southwestern Indian Ocean as a result of strong winds, heavy rainfall and storm surges associated with these systems. Her research showed that Category 5 storms were not present in the South Indian Ocean prior to 1994, but had now become more frequent.
An increase in the ocean temperature is now being recorded over a much larger area, increasing the probability of these high intensity storms. These category 5 storms have also shifted more poleward in their location of origin and landfall over the last three decades. This means that storms which previously existed in the equatorial waters of the central South Indian Ocean, far from any landmasses, are now increasingly occurring in the southern tropical region. That poses a threat to the northern half of Madagascar, Mozambique and to the islands of Reunion and Mauritius.
The last time a category 5 storm hit southern Africa was in April 2016, when tropical cyclone Fantala moved through the southwest Indian Ocean passing north of Madagascar and making landfall on the island of Farquharin the Seychelles. Remarkably, despite being the strongest storm ever to have occurred in the South Indian Ocean, a relatively low $4.5 million in damages was recorded and no deaths were registered. This is in stark contrast to the last category 5 storm that made landfall on Madagascar – Tropical cyclone Gafilo, in March 2004. This cyclone sustained tropical cyclone intensity wind speeds for six days and left at least 250 dead, the sinking of a ferry and left 300,000 people homeless. Unfortunately, southern Africa struggles to cope with the effects of even category 1 tropical cyclones. This suggests that governments are ill equipped to deal with the more powerful category 5 tropical cyclones.
Better forecasting systems need to be put in place so that cities and towns can effectively evacuate before a storm makes landfall to prevent loss of human life. Spatial planning needs to consider this heightened threat, and where possible, discourage development along high-risk coastlines.
Detailed information can be obtained from the following journal :
Fitchett, J.M., 2018. Recent emergence of CAT5 tropical cyclones in the South Indian Ocean. South African Journal of Science, 114(11/12).
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© 2018 Oceanographer Daneeja Mawren