Erosion of Coastal Beaches and Dunes During the Highest Water Level on Record in Southern Maine, USA

As sea level rises, coastal water level records will continue to be broken, leading to increasing damage to coastal ecosystems, infrastructure, and communities. Maine, USA, experienced its highest water level ever recorded on January 13, 2024, just two days after another winter storm with an even higher storm surge on a smaller tide. These two storms destroyed a total of 28% of the dune area along four shorelines we mapped in southern Maine, documented with unoccupied aerial vehicle (UAV) photogrammetry. We found that 1) After the initial storm damage, only 10-50% of the dune volume lost in the storms recovered by the end of the growing season, nine months later. 2) Dunes offer greater stability for coastal sand as hardened infrastructure had greater losses during the storm and higher accretion after. 3) Beaches with southeasterly aspects, perpendicular to the storm winds, experienced 160% more normalized volume loss than beaches with easterly aspects. 4) Scraping and planting combined were 87-91% more effective in annual dune recovery than no action. Given no positive net dune recovery within 9 months after the storm, we suggest that restoration efforts like planting, scraping, and nourishment are needed to ensure dune longevity after record-breaking storm events.