In a dramatic revelation, scientists have confirmed that a colossal megatsunami triggered by a landslide in Alaska last summer is now recognised as the second largest ever documented. This harrowing event, which took place in a remote fjord, underscores the increasing dangers posed by climate change, particularly as glaciers continue to melt and destabilise mountainous regions.
The Catastrophic Event Unfolded
In August 2025, a staggering 64 million cubic metres of rock—equivalent to 24 Great Pyramids—plummeted into the icy waters of Southeast Alaska’s Tracy Arm Fjord. The immense force of this landslide generated a wave that soared to nearly 500 metres in height, wreaking havoc on the landscape. Although this monumental occurrence went largely unnoticed at the time, it has since garnered the attention of researchers who are now piecing together the events leading up to the disaster.
Dr. Bretwood Higman, a geologist based in Alaska, vividly recalls the aftermath of the tsunami, remarking, “It was a close call.” Fortunately, the incident occurred in the early hours of the morning, sparing tourist vessels from potential calamity. “We know that there were people who were very nearly in the wrong place,” he added, expressing concern for future tourists who may unwittingly find themselves in perilous situations.
Understanding Megatsunamis
Megatsunamis, a term used to describe enormous waves generated by landslides, are typically localised phenomena. They can occur when rockfalls—often instigated by earthquakes—plunge into bodies of water. This is distinct from regular tsunamis, which are usually triggered by seismic activity in the ocean and can have far-reaching effects.
The largest recorded megatsunami was over 500 metres high and occurred in the 1950s. The recent incident in Alaska, however, stands as the second most significant in history, raising alarms about the potential for similar occurrences as climate change accelerates glacial melt.
The Role of Climate Change
Recent research published in *Science* draws a direct connection between climate change and the increasing frequency of such hazardous events. The study highlights that as glaciers recede, they lose their ability to stabilise surrounding rock formations. Dr. Stephen Hicks from University College London noted, “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.”
This alarming chain of events signals a worrying trend for both the local environment and the safety of tourists drawn to Alaska’s breathtaking landscapes. “More people are now going to remote areas—often these tourist cruises are to see the natural beauty of the area to actually learn more about climate change—but they are also dangerous places to be,” Dr. Higman cautioned.
Increasing Risks and Future Monitoring
The implications of the recent findings are profound. Both experts agree that the risks associated with megatsunamis are escalating, with Dr. Higman suggesting that such events may now be occurring up to ten times more frequently than they did just a few decades ago. In response to these heightened dangers, some cruise lines have begun to alter their routes, avoiding Tracy Arm due to safety concerns.
There is a consensus among scientists that comprehensive monitoring of potential megatsunami hazards in Alaska is urgently needed. Continuous research and real-time data collection could play a vital role in safeguarding both the environment and human lives in these increasingly precarious coastal areas.
Why it Matters
This alarming megatsunami incident not only serves as a stark reminder of nature’s unpredictability but also highlights the urgent need to address climate change and its far-reaching consequences. As glaciers continue to recede under the pressure of global warming, the risks associated with geological instability will likely escalate, threatening both the environment and human safety. It is imperative that we heed these warnings and take decisive action to mitigate climate change, ensuring that future generations can enjoy the natural wonders of our planet without the looming threat of catastrophic events.