Revising supraglacial rock avalanche magnitudes and frequencies in Glacier Bay National Park, Alaska

A new analysis of supraglacial rock avalanches in Glacier Bay National Park, Alaska, reveals that their frequency and magnitude have been significantly underestimated. Using the Google Earth Engine supraglacial debris input detector (GERALDINE), researchers identified 69 rock avalanches between 1984 and 2020, with a 53% increase over previous estimates. These events were more common at high elevations and along permafrost boundaries, often occurring during warmer months when temperatures facilitated rock-permafrost degradation. A notable surge in debris supply from 2012 to 2016 was driven by three large avalanches contributing 44% of the total debris area. The study suggests that glacial sediment budgets globally may have been underestimated due to detection biases and spatial clustering, highlighting the need for broader investigations in similar remote glaciated regions.

Smith, W. D., Dunning, S. A., Ross, N., Telling, J., Jensen, E. K., Shugar, D. H., Coe, J. A., & Geertsema, M. (2023). Revising supraglacial rock avalanche magnitudes and frequencies in Glacier Bay National Park, Alaska. Geomorphology, 425, 108591. https://doi.org/10.1016/j.geomorph.2023.108591