The effects of windstorm in African medium-sized cities: An analysis of the degree of damage using KDE hotspots and EF-scale matrix

Abstract

Violent windstorms are becoming more prevalent in African inland towns and cities. Yet, very few studies have reported on their increasing occurrences in sub-Saharan Africa's low-density and medium-sized cities and towns. This study uses Enhanced Fujita's F-scale matrix to estimate the intensity and rank the damage severity of a windstorm on June 16, 2018 that ruined more than 30 lives and thousand buildings and other essential structures within the 2-h of its destructive span in Bauchi city in northern Nigeria. A pictorial ranking of some typical damage was carried out to supplement the results of the F-scale decision matrix. In total, 1,236 buildings and structures were identified with varying levels of damage. Two techniques - Average Nearest Neighbor and Kernel Density Estimation (KDE) were implemented using Geographic information system (GIS) in mapping out the spatial patterns and damage hotspots. The results of the F-scale matrix reveal that the dominant wind speed with the most significant damage to buildings and structures is 67 ± 20 ms – 1 with the traditional parts of the city being the worst hit by the disaster. The art and science of visual ranking and hotspots mapping can support policymakers, first respondents, and other stakeholders to co-design strategies and co-produce effective solutions for the increasing climate extreme events and their related disaster risk.