‘Unprecedented’: Alaska had the second-tallest tsunami ever recorded in 2025, with zero warning
Alaska's News Source • • nation
Key Points:
- A massive landslide in a Southeast Alaska fjord on August 10, 2025, triggered a tsunami with a run-up height of 1,578 feet, making it the second-highest tsunami run-up ever recorded globally.
- The landslide, roughly the size of 12 city blocks, fell into a deep fjord near the South Sawyer Glacier, generating a tsunami wave about 330 feet high that traveled at over 150 mph and caused flooding up to 30 miles away.
- The tsunami went largely undetected initially, with no injuries reported, but researchers warn that if ships had been in the fjord, fatalities could have occurred.
- Scientists link the landslide to the retreat of the glacier, which destabilized the slope, and note preceding seismic activity indicating hillside movement before the collapse.
- The event highlights gaps in Alaska’s monitoring systems, as such large landslides are not currently detected, prompting concern over future hazards in the region and leading some cruise lines to avoid the area.
