Coastal erosion and sediment reworking caused by hurricane Irma – implications for storm impact on low?lying tropical islands

Hurricane Irma (September 2017) was one of the most devastating hurricanes in recent times. In January 2018, a post-hurricane field survey conducted on Anegada (British Virgin Islands) to report erosional and depositional evidence caused by Irma's storm surge waves. We document type extent hurricane-induced geomorphological changes, allowing for an improved risk assessment hurricane-related inundation low-lying islands carbonate platforms. Anegada's north shore impacted Irma. The reached about 3.8 m above sea level onshore flow depths ranged between 1.2 1.6 m. Storm wave action created 1 1.5 high scarps along beaches, coastline locally retreated 6 8 Onshore sand sheets up 40 inland, overlie sharp erosive contact have thicknesses 7 35 cm shore. contrast, lobate overwash fans south are 2 10 thick reach 30 inland. Moreover, hurricane reworked pre-existing coast-parallel coral rubble ridge central crest shifted inland due landward transport cobbles boulders (maximum size 0.5 m3) that were part pre-hurricane ridge. A re-survey, 18 months after event, assessed degree natural coastal recovery. northern shoreline eroded during stored shallow water, acted as nearshore source beach reconstruction which set only days event. Beach recovery peaked February when beaches accreted within hours nor'easter-like transported large volumes back onto beach.