Storm Events Along the Coasts of Senegal

Coastal storms pose a growing environmental threat due to their increasing intensity and the damage they inflict on vulnerable coastal communities. This study analyzes coastal storm activity along the Senegalese coastline from 1993 to 2023, focusing on four major cities: Dakar, Saint-Louis, Mbour, and Cap-Skirring. Storms were identified using a Peaks Over Threshold (POT) approach based on the 95th percentile of significant wave height, fitted to a Generalized Pareto Distribution (GPD). Wave data from the ERA5 reanalysis and complementary meteorological and oceanographic datasets were used to characterize storm events. Statistical analyses reveal a heterogeneous spatial distribution of storms. The Mann-Kendall trend test shows a rising frequency of storms in Saint-Louis, Mbour, and Cap-Skirring, while a decreasing trend is observed in Dakar. Conversely, extreme coastal water levels (ECWL) show an increasing trend in Dakar but a decline in the other three cities. Pearson correlation analysis suggests that the Atlantic Multidecadal Oscillation (AMO) strongly influences these regional variations, particularly the observed mismatch between storm frequency and ECWL trends. The most intense storms, based on energy content (Es), occur in descending order in Dakar, Saint-Louis, Mbour, and Cap-Skirring. A positive linear relationship is found between storm duration and intensity, indicating that longer events tend to be more energetic. Seasonally, most storms occur during the dry season (November to May). Wave direction plays a significant role: west-northwest swells dominate the most energetic storms in Dakar and Saint-Louis, while Mbour and Cap-Skirring show more directional variability. Low to moderate intensity storms are generally associated with west-northwest and north-northwest waves. This study provides the first comprehensive analysis of coastal storms along both the northern and southern coasts of Senegal. The findings offer essential insights for policymakers, coastal managers, and local communities to improve coastal risk mitigation strategies amid rising sea levels.