Overview
- A peer-reviewed Science study released Wednesday confirms the Aug. 10, 2025 Tracy Arm landslide drove a tsunami about 481 meters up the fjord, the second-highest runup ever recorded.
- About 64 million cubic meters of rock fell roughly 1,000 vertical meters around 5:26–5:30 a.m., generating a magnitude 5.4–equivalent seismic signal and days of sloshing in a narrow, steep-walled inlet that can amplify waves.
- The team links the collapse to rapid retreat of South Sawyer Glacier, which had pulled back hundreds of meters in the prior months and removed the ice support that helped hold the slope in place.
- Seismic networks recorded tiny tremors in the week before the failure, and researchers say those signals could enable staged alerts if agencies build a landslide-to-tsunami monitoring and warning system.
- The early-morning timing spared visitors, and several cruise lines have altered 2026 routes as scientists urge expanded mapping and real-time monitoring to cut growing risks in glacier-fed fjords.