Long-term monitoring of storm impacts on coastlines of San Salvador Island, Bahamas: a retrospective on October 2015 Hurricane Joaquin

San Salvador’s small size, low relief, and location on the easternmost carbonate bank of the Bahama Archipelago make it highly vulnerable to tropical cyclones. In October 2015, Hurricane Joaquin passed over the island as a strong Category 3 storm. Joaquin waves significantly modified coastal boulder deposits at two sites monitored since 2012: 1) Singer Bar Point (SBP) along the relatively low-energy, gently seaward-sloping ramp on the lagoon- and reef-protected north coast; and 2) rocky cliff bench, 3–5 meters above sea level, at The Gulf (TG) on the high-energy south coast. Storm waves overtopped TG cliffs and modified the sharp-crested, narrow boulder ridge into a broad, vegetation-free field. New boulders up to 3 m in diameter were emplaced on cliffs, and 1–3 ton blocks from prior storms moved up to 26 m inland. Calculated flow velocities needed to initiate their transport were 2.6–5.7 m/s. The boulder-ridge edge moved landward 4–5 m, exposing a Pleistocene/Holocene boundary reddish caliche horizon that marked the extent of storm erosion.

On the sandy east coast, the dune and beach system adjacent to the Fortune Hill Cemetery, whose seaward-facing wall was destroyed and replaced by a ~2 m vertical foredune scarp by Joaquin waves, experienced full recovery and was not significantly eroded by Hurricane Melissa that made landfall on San Salvador as a Category 1 storm in October 2025, ten years after Joaquin. Melissa waves moved small boulders and finer-grained sediment within a seaward-sloping reentrant at TG. Similar modifications are expected at SBP site which is also frequently impacted by northerly winter storms. Detailed surveys are needed to fully assess Melissa’s impacts, but the fact that TG cliffs remained mainly unaltered post-Joaquin and pre-Melissa, except for vegetation re-growth, and the striking differences documented immediately before and after Joaquin illustrate the profound consequences of this extreme weather event.