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On August 10, 2025, 64 million cubic meters of mountainside collapsed into Alaska's Tracy Arm fjord near the retreating South Sawyer Glacier, generating a megatsunami with a runup of 481 meters (1,578 feet) — second only to the 1958 Lituya Bay event. The wave struck at 5:26 a.m. on a rainy morning when no vessels were in the immediate impact zone, averting what researchers say could have been a mass-casualty disaster in a corridor that hosts up to 20 boats and six cruise ships daily during peak season.