Nathaniel Ross Baurley , Jane K Hart

We utilised repeat high-resolution UAV-SfM surveys, alongside terrestrial photography acquired in-situ, to investigate, for the first time, the role of thermal notch erosion in forcing localised calving failure and subsequent short-term increases in velocity at a lake-terminating glacier. This data was acquired daily (where possible) across one week in July 2019 and two weeks in July 2021 to provide insights into a suite of processes that are presently under-studied. We demonstrate that high-magnitude calving (surface area >1000 m2), 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 and overall stability of both freshwater and tidewater glaciers, warranting further research into these key processes.