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Massive wave strikes remote Alaskan fjord
A section of an Alaskan mountain collapsed into the sea last summer, generating a 500-metre wave-ranked as the second-highest megatsunami ever documented. Scientists warn the event underscores growing risks linked to melting glaciers.
Landslide triggers near-disaster
Approximately 64 million cubic metres of rock-equivalent to 24 Great Pyramids-plunged into Tracy Arm Fjord in under a minute. The impact produced a wave nearly 500 metres tall, according to a new study published in Science.
Researchers noted the timing-early morning-spared tourist cruise ships from potential catastrophe. Dr. Bretwood Higman, an Alaskan geologist who surveyed the damage, called it "a close call."
"We know that there were people who were very nearly in the wrong place. I'm quite terrified that we're not going to be so lucky in the future."
Dr. Bretwood Higman, geologist
How megatsunamis differ from ocean tsunamis
Megatsunamis occur when landslides-often triggered by earthquakes or unstable rock-displace water in confined areas like fjords. Unlike earthquake-driven tsunamis, which can cross oceans, megatsunamis are typically localized and dissipate rapidly.
The largest recorded megatsunami, in the 1950s, exceeded 500 metres. The Alaska event now ranks second.
Climate change amplifies risks
Scientists attribute the increased frequency of such collapses to retreating glaciers. Dr. Stephen Hicks of University College London explained that the glacier at Tracy Arm had previously stabilized the cliff face. As the ice melted, the exposed rock became vulnerable to sudden collapse.
"More people are visiting remote areas to witness climate change impacts firsthand-yet these locations are becoming increasingly hazardous."
Dr. Stephen Hicks, University College London
Call for expanded monitoring
Dr. Higman estimates megatsunami risks have risen tenfold over recent decades. Researchers are urging broader hazard monitoring in Alaska's vulnerable regions, where steep terrain and frequent earthquakes compound the threat.
Some cruise operators have already halted visits to Tracy Arm amid safety concerns.
