The role of thermal notch erosion in forcing localised calving failure and short-term increases in velocity at a lake-terminating glacier in southeast Iceland

We utilised repeat high-resolution UAV-SfM surveys, alongside terrestrial photography acquired in-situ, to investigate, for the first time, how localised calving failure can drive short-term increases in velocity at a lake-terminating glacier. This data was acquired over five days in early July 2019, and across 11 days in July 2021, to provide insights into a suite of processes that have been rarely studied. We demonstrate that We demonstrate that large calving events (surface area >1000 m2, >150 m wide), occurring as a direct result of thermal notches at the waterline, can drive short-term increases in velocity up to 30% above the average, which are sustained for several days and occur over a much larger area of the glacier than was originally impacted by the initial calving event. We suggest that these findings present an important, yet previously undocumented aspect of the dynamic behaviour of both freshwater and tidewater glaciers, warranting further research into these key processes.