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A Sudden Landslide Triggered Alaska's 2025 'Mega-Tsunami.' Now, Scientists Have Identified Warning Signs to Predict Similar Events
Key takeaways
- A view of the landslide and tsunami aftermath a few days after the catastrophic events Cyrus Read / U.S.
- Despite being the second-largest landslide-induced tsunami on record, the event went largely unreported at the time.
- “Normally, with these gigantic rock avalanches, they often give some sort of warning signs in the weeks, months, years prior when the slope is slowly moving down the mountain.
A view of the landslide and tsunami aftermath a few days after the catastrophic events Cyrus Read / U.S. Geological Survey In the early morning hours of August 10, 2025, a massive landslide caused at least 2.3 billion cubic feet of rock—roughly 24 times the volume of the Great Pyramid of Giza—to plummet into Tracy Arm fjord. It’s a popular tourist destination around 45 miles south of Juneau, Alaska. The ensuing splash triggered a “mega-tsunami,” with a wave rising around 1,580 feet above sea level on the other side of the body of water.
Despite being the second-largest landslide-induced tsunami on record, the event went largely unreported at the time. Luckily, no one was injured.
Now, a study published in the journal Science on May 6 details what happened and identifies possible warning signs of landslides based on satellite images, eyewitness accounts, earthquake detector data and computer simulations. Understanding the lead-up to this “near-miss” event can help regional stakeholders create better monitoring and alert systems, especially as the risk of landslide-generated tsunamis rises due to glacier melt driven by climate change.