INVESTIGATING HOW CLIMATE CHANGE IS IMPACTING STORM-INDUCED EROSION IN COASTAL ALASKA

Alaska is experiencing amplified geomorphological hazards due to climate change, yet given its unique and extreme environment, limited data exist that document these increasing threats. Alaska’s coastal communities are becoming increasingly more vulnerable to erosion associated with the escalating frequency and severity of storms, compounded by permafrost degradation. Meanwhile, local and statewide hazard mitigation decisions require a defined understanding of current and projected risk. However, many rural Alaskan communities lack the baseline data, historical storm records, and/or assessments of impacts necessary to develop well-informed strategies. Recent high-resolution elevation data were collected in Wainwright, Alaska, before and after a significant storm that occurred in northern Alaska in October 2022. These data make it possible to quantify the significant amount of erosion that was caused by this single storm event and help evaluate the efficacy of existing erosion mitigation efforts such as a rock revetment and sandbags that have been placed along the community’s coastline. Digital surface models created from unmanned aerial vehicle surveys collected in 2021 and 2023 are combined with measured coastal topographic profiles to quantify erosion and volumetric land loss. Land loss is especially high where no coastal protection was implemented, but the greatest land loss is observed where unprotected sections of coastline lie between discontinuous protected sections. This study highlights an opportunity for community-led data collection that would increase the temporal resolution of data collection and help guide future activities aimed at coastal hazard assessment and mitigation. Additionally, when placed in the context of longer-term temperature, weather, and sea ice data, this work provides insights into to the possible future impacts of emergent Arctic storm events and may help guide the development of erosion mitigation strategies that can ensure the resilience of Alaska's coastal communities facing a changing climate.