A colossal tsunami, taller than New York City's Empire State Building, struck Tracy Arm Fjord in southeastern Alaska on 10 August 2025, researchers have revealed. The wave reached 1,578 feet (481 metres), making it the second-highest ever recorded. The tsunami was caused by a landslide that scientists say was a direct consequence of global warming.
The landslide occurred at 5:30am, meaning no cruise ships or other vessels were present in the popular sightseeing destination, resulting in no injuries. The glacier that once buttressed the mountain had retreated significantly due to rising temperatures, leaving the rock face unsupported. Dan Shugar, a geomorphologist at the University of Calgary and lead author of the study published in Science, warned: 'The fact that the landslide occurred this early in the morning was unbelievably lucky. Next time - and there will be a next time - we may not be so lucky.'
Scientists reconstructed the event using aerial photos, satellite and seismic data, fieldwork, and accounts from people nearby. They determined the wave height by measuring where vegetation had been stripped from the rock walls, leaving dramatic scars. About 83 million cubic yards (64 million cubic metres) of rock collapsed in about one minute - 24 times the volume of the Great Pyramid of Giza, according to University College London geophysicist and study co-author Stephen Hicks.
The collapse triggered a seismic wave observed globally. Some waves became trapped in the fjord, causing a seiche - sloshing of water - that lasted several days. Seismic data showed warning signs: the landslide was preceded by about a week of tiny earthquakes indicating fracturing. Hicks said this offers hope for developing warning systems.
The tallest tsunami on record - about 1,700 feet (520 metres) - also occurred in Alaska, in Lituya Bay in 1958. By comparison, the 2004 Indian Ocean tsunami reached 167 feet (51 metres) and the 2011 Japan tsunami about 131 feet (40 metres).
