Assessing Tropical Cyclones risks in Comoros Islands Using Geospatial Technologies

Abstract

Tropical cyclones (TCs) are major natural hazards in the Indian Ocean region, particularly in the Comoros Islands, which are regularly hit by tropical cyclones, the latest of which was Cyclone Kenneth in April 2019. The intensity and extent of TCs and their impacts are likely to increase in the future due to climate change. It is therefore essential to carry out a proper cyclone risk assessment, create risk maps and to identify areas where TCs risks are relatively high to minimize potential losses caused by these cyclones. This study developed a multi-criteria spatial approach to map the levels of TCs risk using geospatial technologies to quantify the degree of risk in all the prefectures of the Comoros. A total of 14 spatial criteria covering three risk components vulnerability and exposure, hazard and mitigation capacity were taken into account. A spatial layer was then generated for each criterion with a weighted score using the Analytic Hierarchy Process (AHP) and ArcGIS. Map were then produced for all risk components, and a final cyclone risk map was produced considering vulnerability, hazard and mitigation capacity components. The maps obtained were then used to identify the spatial extent and levels of risk considering four levels (very high, high, moderate, low and very low). The results indicated that the prefecture of Ouani area was more vulnerable to TCs, due to its low altitude, low slopes, being close to the costs, large number of historical cyclone paths and the high population density. The methodological approach and results were then validated by a qualitative assessment carried out in the field. Finally, cyclone risk reduction strategies were suggested. This study has potential and valuable implications for experts and policymakers as it provides a solid basis for the development of national risk maps and mitigation strategies to reduce the disastrous impacts of TCs