Investigating the connection between metocean conditions and coastal user safety: An analysis of search and rescue data

Abstract

South Africa hosts a multitude of interests along its coastline and in its coastal waters. These range from recreational and small-scale commercial activities to those related to tourism and large-scale industry. The associated need for robust coastal risk management is key in securing both economic interests and safety of life. Despite widespread intuitive appreciation of the relationship between weather and coastal safety, objective analysis in this regard is lacking. This study strives to address this gap to assist, for example, coastal management, the efficient deployment of search and rescue (SAR) resources and investment in safety infrastructure. Further, we used statistical relationships between weather and incident-occurrence to develop a basic risk characterisation framework for different coastal areas and activities. Results from our investigation revealed varying sensitivities to coastal marine meteorological parameters. For activities in which individuals are more inherently vulnerable (e.g. swimming), incidents were most frequent during Good conditions. For activities involving small personal water craft (e.g. kayaks), incidents were most frequent during Marginal conditions. Incidents involving small vessels (e.g. rigid-inflatable boats) were most numerous during Bad conditions, with no clear pattern in respect of larger, commercial vessels (e.g. fishing trawlers). Finally, we present empirically derived risk coefficients, showing the relationship between risk, user vulnerability and user exposure for given weather severity scenarios.