A recent scientific investigation has unveiled the astonishing magnitude of a megatsunami that struck the remote fjords of southeast Alaska last summer, marking it as the second highest wave ever recorded. Generated by a staggering landslide, this colossal wave serves as a stark reminder of the perils associated with climate change and the rapid melting of glaciers in the region.
The Catastrophic Event
In August 2025, a cataclysmic event unfolded when approximately 64 million cubic metres of rock—equivalent to a staggering 24 Great Pyramids—plummeted into the ocean from a crumbling Alaskan mountain. The resulting wave soared to nearly 500 metres in height, devastating the surrounding landscape. Fortunately, the early morning timing of the incident spared tourist vessels from the destruction, as researchers noted that cruise ships were in port at the time.
Dr Bretwood Higman, a geologist based in Alaska, witnessed the aftermath of the disaster at Tracy Arm Fjord. He remarked, “It was 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.”
Understanding Megatsunamis
Megatsunamis differ significantly from their oceanic counterparts, which are triggered by seismic activity or underwater volcanic eruptions. The former occur when a landslide—often instigated by earthquakes or unstable rock—collapses into a body of water, producing localised and rapidly dissipating waves. The largest megatsunami on record, occurring in the 1950s, surpassed 500 metres in height.
Dr Higman’s exploration of the Tracy Arm area revealed a landscape scarred by the event. Broken trees littered the mountainside, and extensive patches of bare rock were visible where soil and vegetation had been stripped away.
Climate Change and Increased Risks
Recent research published in the journal Science indicates a concerning connection between glacier melt due to climate change and the frequency of such landslides. Scientists, including Dr Stephen Hicks from University College London, have identified that retreating glaciers, which previously stabilised rocky cliff faces, now leave these structures vulnerable to collapse. “When the ice retreated, it exposed the bottom of the cliff face, allowing that rock material to suddenly collapse into the fjord,” explained Dr Hicks.
As tourism in these breathtaking yet treacherous locations increases, experts warn that visitors are unwittingly placing themselves in harm’s way. The beauty of the Alaskan wilderness, often a draw for cruise ships, masks the potential dangers lurking in these remote areas.
Rising Frequency of Megatsunamis
Dr Higman expressed a troubling outlook on the future, stating, “At this point, I’m pretty confident that these events are increasing not just slightly, but significantly—perhaps by as much as ten times more frequent than they were just a few decades ago.” This alarming trend has prompted calls for enhanced monitoring of regions in Alaska that are susceptible to megatsunami events.
In response to these growing safety concerns, several cruise companies have decided to halt operations in Tracy Arm, prioritising passenger safety over the allure of these majestic landscapes.
Why it Matters
The emergence of this megatsunami as the second largest ever recorded serves as a vital warning about the escalating risks posed by climate change. As glaciers continue to melt and destabilise the geological landscape, the potential for catastrophic events like this increases, endangering both local ecosystems and human lives. Enhanced awareness and monitoring are crucial to safeguarding both the environment and those who seek to explore its magnificence.