In a striking revelation, scientists have uncovered that a monumental wave, triggered by a landslide in Alaska, ranks as the second tallest megatsunami ever documented. This extraordinary event, which occurred last summer, serves as a potent reminder of the escalating dangers presented by climate change and the melting glaciers that line the Alaskan coast.
The Catastrophic Event
In August 2025, a colossal wave surged through a remote fjord in southeast Alaska, leaving a trail of destruction that went largely unnoticed at the time. Recent scientific analysis has traced its origins back to a massive landslide, where approximately 64 million cubic metres of rock—equivalent to the weight of 24 Great Pyramids—plummeted into the waters below. The sheer force generated by this rapid descent created a wave that reached heights of nearly 500 metres.
Researchers have pointed out that the timing of this event was fortuitous; occurring in the early hours of the morning, it avoided potential disaster for tourist cruise ships that frequent the area. Dr. Bretwood Higman, a geologist from Alaska who witnessed the aftermath at Tracy Arm Fjord, described it as “a close call.” He expressed concern over future occurrences, stating, “I’m quite terrified that we’re not going to be so lucky in the future.”
Understanding Megatsunamis
Megatsunamis are distinct from typical tsunamis, which are often triggered by seismic activities in the open ocean. The latter can travel vast distances and wreak havoc on coastal communities, as seen in the tragic 2011 tsunami in Japan. In contrast, megatsunamis are usually localised phenomena, resulting from landslides—often due to earthquakes or the destabilisation of rock—and tend to dissipate more quickly.
Historically, the largest recorded megatsunami occurred in the 1950s, reaching over 500 metres. This latest incident has now claimed the title of the second largest ever recorded.
The Role of Climate Change
Alaska’s unique geographical features—including steep mountains, narrow fjords, and frequent seismic activity—make it particularly susceptible to megatsunamis. Recent research published in the journal Science connects the dots between climate change and the increasing frequency of such catastrophic events. With glaciers melting at an alarming rate, the stability of these mountainous regions is compromised.
Dr. Stephen Hicks from University College London noted that the retreat of glaciers previously acted as a stabilising force for certain rock formations. As these icy structures diminish, they expose cliff faces to collapse, as seen in the recent landslide. “The glacier was helping to hold up this piece of rock,” he explained, underscoring the direct link between environmental changes and geological instability.
Rising Risks and Future Precautions
The implications of this research are profound. More people are venturing into remote Alaskan areas, often as part of eco-tourism initiatives aimed at witnessing the natural beauty and understanding the effects of climate change. However, as Dr. Higman warned, these beautiful landscapes are also perilous. He confidently stated that the risks of megatsunamis are escalating significantly, possibly by a factor of ten compared to previous decades.
In response to these heightened risks, scientists are advocating for enhanced monitoring of potential hazards in vulnerable regions of Alaska. Some cruise companies have already begun to reconsider their itineraries, announcing that they will cease sending vessels into Tracy Arm amidst safety concerns.
Why it Matters
The recent megatsunami in Alaska starkly illustrates the urgent need for increased awareness and preparedness in the face of climate change. As glaciers continue to recede and geological instabilities rise, the potential for catastrophic events grows. By understanding the science behind these occurrences and prioritising safety measures, we can better protect both the pristine environments we cherish and the lives of those who explore them. The time to act is now.