August 2025 Rockslide Tsunami Reached 1,500+ Feet In Height In Alaskan Fjord Routinely Visited By Cruise Ships
A mega tsunami in Alaska last year in a fjord visited by cruise ships is a stark warning of the risks of coastal rockslides and glacier retreat fueled by the climate crisis, a new study warns. Scientists recorded the world’s second-tallest tsunami after it struck the Tracy Arm fjord in south-east Alaska last August after a massive rockslide around the toe of a glacier. The tsunami reached 481 metres (1,578ft) in height; by comparison the Eiffel Tower is 330 metres (1082ft).
According to the new research published in Science on Wednesday and led by Dan Shugar, a geomorphologist of the University of Calgary, the sequence began at 5.26am local time on 10 August 2025. A large landslide collapsed 1km vertically onto the South Sawyer glacier and into the narrow, 48km fjord, producing the huge tsunami.
There were no fatalities at the early hour but the area is visited by approximately three cruise ships passing through daily, along with other vessels traveling within a few kilometers of the landslide site. Just hours after the landslide, a sightseeing vessel from Juneau and a National Geographic tour boat – each capable of carrying more than 100 passengers, were due to enter the fjord. The day before, two cruise ships carrying thousands of passengers had already visited the area, with another scheduled to arrive the following day.
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They also noted that the tsunami was only slightly smaller than the world’s tallest, recorded in Lituya Bay, Alaska, in 1958 at 530 metres (1,728ft). The Tracy Arm event also triggered a 36-hour seiche – a standing wave that oscillates within a closed body of water. The study further found that the landslide generated long-period seismic waves equivalent to those of a 5.4 magnitude earthquake.Eyewitness accounts in the report highlighted the tsunami’s far-reaching effects. A group of kayakers camping on Harbor Island, about 55km away, reported water surging past their tent, sweeping away one of their kayaks along with other gear.
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https://www.theguardian.com/us-news/2026/may/06/alaska-mega-tsunami-climate-change-glacier