Alaska Megatsunami Ranked Second Tallest On Record After Massive Landslide
Alaska Megatsunami

Alaska Megatsunami Ranked Second Tallest On Record After Massive Landslide

Mintesinot Niggusie

A giant wave triggered when part of a mountain collapsed into the sea in southeast Alaska last year has been identified as the second tallest megatsunami ever recorded, according to a new scientific analysis that highlights growing risks linked to unstable, warming landscapes.

The event occurred in a remote fjord where a massive landslide sent an estimated 64 million cubic metres of rock into the water in less than a minute. Scientists say the volume is equivalent to about 24 Great Pyramids.

That sudden impact generated a wave nearly 500 metres high, sweeping through Tracy Arm Fjord and leaving visible destruction along its path. Researchers say the timing of the collapse in the early hours of the morning likely prevented a far worse outcome, with tourist cruise ships absent from the area at the time of the event.

Dr Bretwood Higman, an Alaskan geologist who visited the site, described the incident as narrowly avoided disaster. “We know that there were people that were very nearly in the wrong place,” he said. “I’m quite terrified that we’re not going to be so lucky in the future.”

The study links the megatsunami to a large rock landslide, a mechanism that can be triggered when unstable slopes or earthquake activity send material crashing into water bodies. Megatsunamis differ from ocean-crossing tsunamis, which are typically generated by undersea earthquakes and can travel across entire oceans, striking distant coastlines with destructive force.

By contrast, megatsunamis are usually highly localised, dissipating quickly but producing extreme wave heights near the impact zone. The largest recorded megatsunami occurred in the 1950s and exceeded 500 metres in height, placing the Alaska event as the second largest known occurrence.

Scientists say the findings highlight the growing instability of glacial and mountainous regions, where warming conditions are increasing the likelihood of large-scale landslides into fjords and coastal waters.