Glacier Retreat Increases Likelihood of Landslides and Tsunamis

Science, 6 May 2026

An August 2025 landslide in Tracy Arm fjord, Alaska, generated one of the largest tsunamis in recorded history, with water and debris reaching 481 meters up the opposite fjord wall and then surging through the valley. The failure occurred at the edge of South Sawyer Glacier, where long-term glacier retreat and rapid ice loss exposed and destabilized steep mountain slopes. Days before collapse, the glacier and surrounding slope showed signs of weakening, including rapid calving and thousands of small seismic tremors. The landslide highlights how retreating glaciers can remove structural support from adjacent rock walls, allowing ice loss to directly trigger landslides that transfer enormous rock mass into water and generate tsunamis. Similar landslides have been occurring from Alaska to Greenland and Norway, suggesting a broader cryosphere-linked hazard where warming and ice loss are reshaping mountain stability and increasing coastal risk in fjord environments.

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