A recent scientific analysis reveals that a colossal megatsunami, triggered by a massive landslide in Alaska, stands as the second largest wave ever recorded. Occurring in August 2025, this extraordinary event underscores the escalating dangers posed by melting glaciers and the geological instability they engender. The incident, which largely flew under the radar at the time, has prompted urgent calls for greater monitoring of potential hazards in the region.
The Catastrophic Event
In the early hours of a summer morning, a staggering 64 million cubic metres of rock—equivalent to the volume of 24 Great Pyramids—plummeted into a fjord near South Sawyer Glacier. This monumental landslide generated a wave that surged nearly 500 metres high, obliterating everything in its path. Fortunately, the timing spared tourist cruise ships from disaster, as they were not present during the early morning hours.
Dr. Bretwood Higman, a geologist with firsthand experience of the destruction at Tracy Arm Fjord, reflected on the near-miss. “It was a close call,” he stated. “We know that there were people that 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 more familiar counterparts. They are typically local phenomena, resulting from landslides caused by earthquakes or the instability of loose rock, and dissipate quickly. In contrast, traditional tsunamis, such as the catastrophic event in Japan in 2011, are triggered by seismic activity in the ocean and can travel vast distances, wreaking havoc on coastal communities.
The largest megatsunami on record occurred in the 1950s, surpassing 500 metres in height. The recent Alaska wave claims the second spot, raising alarms among scientists about the increasing frequency of such events.
The Role of Climate Change
New research published in the journal *Science* highlights the alarming connection between climate change and the rising threat of megatsunamis. As glaciers melt, they destabilise the surrounding rock formations, heightening the risk of landslides. Dr. Stephen Hicks from University College London noted that the glacier had previously “helped to hold up this piece of rock.” With the ice retreating, the cliff face became vulnerable, leading to the sudden collapse into the fjord.
Dr. Higman emphasised the gravity of the situation, asserting, “At this point, I’m pretty confident that these are increasing not just a little bit, but increasing a lot. Maybe in the order of ten times as frequent as they were just a few decades ago.”
A Call for Caution
As more tourists flock to Alaska to witness its breathtaking natural beauty and learn about climate change, the inherent dangers of the region cannot be ignored. Some cruise lines have already announced their decision to avoid Tracy Arm due to safety concerns, reflecting a growing awareness of the risks involved.
The combination of steep mountains, narrow fjords, and frequent seismic activity makes Alaska particularly susceptible to megatsunamis. Researchers are advocating for enhanced monitoring systems to identify and mitigate risks in vulnerable areas.
Why it Matters
The implications of this megatsunami extend far beyond Alaska’s remote fjords. As climate change continues to reshape our planet, the threat of geological disasters looms larger than ever. This event serves as a cautionary tale, highlighting the urgent need for awareness and preparedness as we confront the realities of a warming world. With more people venturing into these stunning yet perilous landscapes, the potential for catastrophe demands immediate attention and action from both scientists and policymakers alike.
