Massive 500-meter 'megatsunami' hits Alaska Fjord after part of mountain collapses

After the part of an Alaskan mountain crumbled into the sea, a massive 'megatsunami' wave was created, marking the second-tallest ever, reminding the risks posed by melting glaciers, according to scientists. Last year, a giant wave came across a remote fjord in southeast Alaska leading to the destruction in its wake.

The event, which went largely unreported at the time, now shows that small earthquakes resulted in a massive landslide. As a result, 64 million cubic metres of rock, the equivalent of 24 Great Pyramids, splashed into the water, creating a gigantic wave almost 500 metres tall. In response, Dr Bretwood Higman, an Alaskan geologist who witnessed the damage at Tracy Arm Fjord, stated that it was "a close call". "We know that there were people who 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."

Massive waves known as megatsunamis occur when landslides, triggered by earthquakes or unstable rock, crash into bodies of water. These events are typically confined to local areas and lose strength quickly. In contrast, ocean-wide tsunamis are usually caused by earthquakes or, at times, underwater volcanic activity.

Such tsunamis, like the 2011 Japan disaster, can travel vast distances, striking populated coastlines and causing extensive destruction and loss of life. The largest recorded megatsunami occurred in the 1950s, exceeding 500 metres in height, with the recent event ranking as the second largest. When Dr Higman reached the Tracy Arm Fjord—an Alaskan cruise destination—weeks after the event, he observed shattered trees scattered across slopes and waters, along with large expanses of exposed rock where soil and vegetation had been stripped away.

Vulnerability of Alaska

Alaska is mainly vulnerable to megatsunamis because of its narrow fjords, steep mountains and frequent earthquakes. The new research published in Science indicates that glacier melt due to climate change is making it even worse. Dr Stephen Hicks of University College London stated that the glacier was previously "helping to hold up this piece of rock", and so when the ice retreated, it exposed the bottom of the cliff face, "allowing that rock material to suddenly collapse into the fjord".

Stephen's team have studied tsunamis for almost 10 years and is worried about it. "More people are now going to remote areas - often these tourist cruises are going to see the natural beauty of the area to actually learn more about climate change - but they are also dangerous places to be," he added.