A monumental megatsunami triggered by a landslide in Alaska has been identified as the second tallest on record, highlighting the escalating dangers posed by climate change and glacial melting. This significant event, which transpired in August 2025 near the South Sawyer Glacier, has drawn attention to the fragile balance of the region’s geology and the potential risks for increasing tourist activity in these remote areas.
The August 2025 Event
Last summer, a colossal wave surged through the tranquil fjords of southeast Alaska, resulting from a landslide that unleashed approximately 64 million cubic metres of rock—an astonishing volume comparable to 24 Great Pyramids. The sheer force of this rock entering the water within a mere minute generated a wave reaching nearly 500 metres in height. Fortunately, the timing of the event, occurring in the early hours, spared tourist vessels from disaster, though experts warn that future occurrences may not be so fortuitous.
Dr. Bretwood Higman, a geologist from Alaska who surveyed the aftermath at Tracy Arm Fjord, described the situation as a “close call” and expressed concern over the proximity of tourists to such hazardous environments. “We know that there were people that were very nearly in the wrong place,” he stated, emphasising the urgent need for awareness regarding these geological phenomena.
Understanding Megatsunamis
Megatsunamis are distinct from typical tsunamis; they occur when substantial land movements, such as landslides—often triggered by earthquakes—displace large volumes of water. Unlike traditional tsunamis, which can traverse vast ocean distances, megatsunamis typically remain localized but possess the capacity to cause immense destruction in their immediate vicinity.
Historically, the largest recorded megatsunami occurred in the 1950s, surpassing 500 metres in height. This recent incident, while the second highest, serves as a critical reminder of the geological volatility of Alaska, which is characterised by steep mountains, narrow fjords, and frequent seismic activity.
Climate Change and Increasing Risks
Recent research published in the journal *Science* has begun to unravel the connection between climate change and the frequency of such geohazards. The study highlights that the melting of glaciers, exacerbated by rising temperatures, is destabilising the cliffs that overlook these fjords. Dr. Stephen Hicks from University College London noted that glaciers previously acted as stabilising forces, and their retreat has exposed cliff faces to collapse, leading to catastrophic landslides.
Dr. Higman has been studying tsunamis for decades and expressed his growing alarm. “At this point, I’m pretty confident that these are increasing not just a little bit, but increasing a lot,” he warned. “Maybe in the order of 10 times as frequent as they were just a few decades ago.” The implications of this rise are profound, especially as tourism to these breathtaking yet perilous locales continues to grow.
Industry Response and Future Monitoring
In light of these findings, there is a pressing need for enhanced monitoring of potential megatsunami hazards in susceptible Alaskan regions. Some cruise lines have already announced plans to cease operations in Tracy Arm, prioritising passenger safety amid these newfound risks.
As climate change reshapes the landscape, the potential for geological disasters is becoming increasingly apparent. The delicate interplay between our planet’s natural systems and human activity necessitates immediate attention and action.
Why it Matters
The recent megatsunami serves as a stark illustration of the intersection between climate change and geological hazards, urging both the scientific community and the public to recognise the risks associated with global warming. As more individuals flock to Alaska’s awe-inspiring landscapes, the need for robust safety measures and comprehensive geological monitoring has never been more critical. This event is not merely an isolated incident; it is a harbinger of what may become a more frequent reality in a warming world.
