Assessment of a Ground-Based Lightning Detection and Near-Real-Time Warning System in the Rural Community of Swayimane, KwaZulu-Natal, South Africa

Climate change projections of increases in lightning activity are an added concern for lightning-prone countries such as South Africa. South Africa's high levels of poverty, lack of education, and awareness, as well as a poorly developed infrastructure, increase the vulnerability of rural communities to the threat of lightning. Despite the existence of national lightning networks, lightning alerts and warnings are not disseminated well to such rural communities. We therefore developed a community-based early warning system (EWS) to detect and disseminate lightning threats and alerts in a timely and comprehensible manner within Swayimane, KwaZulu-Natal, South Africa. The system is composed of an electrical field meter and a lightning flash sensor with warnings disseminated via audible and visible alarms on site and with a remote server issuing short message services (SMSs) and email alerts. Twelve months of data (February 2018-February 2019) were utilized to evaluate the performance of the EWS's detection and warning capabilities. Diurnal variations in lightning activity indicated the influence of solar radiation, causing convective conditions with peaks in lightning activity occurring during the late afternoon and early evening (between 1400 and 2100) coinciding with students being released from school and when most workers return home. In addition to detecting the threat of lightning, the EWS was beneficial in identifying periods that exhibited above-normal lightning activity, with two specific lightning events examined in detail. Poor network signals in rural communities presented an initial challenge, delaying data transmission to the central server until rectified using multiple network providers. Overall, the EWS was found to disseminate reliable warnings in a timely manner. Significance Statement Thunderstorms and, more specifically, lightning are life-threatening severe weather phenomena that can result in damage to infrastructure, physical injury, and loss of life (human and livestock). South Africa's lightning mortality rate is said to be 4 times the global average. Despite significant progress in lightning detection and monitoring on a national scale, rural communities remain vulnerable and continue to live without any lightning warning. In an attempt to improve lightning detection on a local scale, this study developed and assessed a community-based lightning early warning system. The system has a monitoring and early warning capacity to improve the preparedness of rural communities to lightning, thus mitigating losses.