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

Lookup NU author(s): Dr Will Smith, Dr Stuart DunningORCiD, Professor Neil RossORCiD, Dr Jon Telling



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


The frequency of large supraglacial landslides (rock avalanches) occurring in glacial environments is thought to be increasing due to feedbacks with climate warming and permafrost degradation. However, it is difficult to (i) test this; (ii) establish cause–effect relationships; and (iii) determine associated lag-times, due to both temporal and spatial biases in detection rates. Here we applied the Google Earth Engine supraglacial debris input detector (GERALDINE) to Glacier Bay National Park & Preserve (GLBA), Alaska. We find that the number of rock avalanches (RAs) has previously been underestimated by 53 %, with a bias in past detections towards large area RAs. In total, GLBA experienced 69 RAs during 1984–2020, with the highest frequency in the last three years. Of these, 58 % were deposited into the accumulation zone and then sequestered into the ice within two years. RA sources clustered spatially at high elevations and around certain peaks and ridges, predominantly at the boundary of modelled permafrost likelihood. They also clustered temporally, occurring mainly between May and September when air temperatures were high enough to initiate rock-permafrost degradation mechanisms. There was a chronic background debris supply from RAs, with at least one RA occurring in all but nine years; however, a debris rich period during 2012–2016 was driven by three large RAs delivering 44 % of all (1984–2020) debris (by area). Comparable investigation of slope-failures in other remote currently glaciated regions is lacking. If RA rates are similar elsewhere, especially the bias towards emplacement onto/into accumulation zones, their contribution to glacial sediment budgets has been globally underestimated.

Publication metadata

Author(s): Smith WD, Dunning SA, Ross N, Telling J, Jensen EK, Shugar DH, Coe JA, Geertsema M

Publication type: Article

Publication status: Published

Journal: Geomorphology

Year: 2023

Volume: 425

Online publication date: 24/01/2023

Acceptance date: 16/01/2023

Date deposited: 27/01/2023

ISSN (print): 0169-555X

ISSN (electronic): 1872-695X

Publisher: Elsevier


DOI: 10.1016/j.geomorph.2023.108591


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Funder referenceFunder name
Newcastle University Research Excellence Scholarship