A staggering event unfolded in August 2025 when a massive landslide in southeast Alaska unleashed a megatsunami that stands as the second highest wave ever recorded. This natural disaster serves as a stark reminder of the escalating threats posed by climate change and melting glaciers, scientists warn.
The Unseen Catastrophe
Last summer, a remote fjord in Alaska bore witness to an extraordinary wave, yet the world remained largely unaware of the destruction it wrought. This colossal wave, nearly 500 metres tall, was generated when 64 million cubic metres of rock—equivalent to the weight of 24 Great Pyramids—plummeted into the sea. The sheer force of this landslide created a devastating wave that could have endangered numerous lives, particularly those of tourists aboard cruise ships in the vicinity. Fortunately, the incident occurred in the early hours of the morning, sparing those vessels from the impending chaos.
Dr Bretwood Higman, a geologist from Alaska who surveyed the aftermath at Tracy Arm Fjord, described the situation as 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, unlike their oceanic counterparts triggered by seismic activity, are generated by landslides into bodies of water, typically resulting in localised waves that dissipate quickly. The largest recorded megatsunami occurred in the 1950s, towering over 500 metres. The recent event firmly positions itself as the second largest, raising alarms about the increasing frequency of such occurrences, particularly in Alaska’s vulnerable geography characterised by steep mountains and narrow fjords.
Dr Higman’s exploration of the Tracy Arm Fjord revealed a landscape marred by destruction, with uprooted trees scattered across the mountainside and vast areas of rock stripped bare of soil and vegetation. The dramatic changes to the landscape are not merely a product of natural forces but are increasingly influenced by human-induced climate change.
The Role of Climate Change
Recent research published in the journal *Science* underscores the connection between glacier melting and the frequency of landslides that trigger megatsunamis. Dr Stephen Hicks from University College London explained that as glaciers retreat, they have less capacity to support the rock formations above. “The glacier was previously helping to hold up this piece of rock,” he noted. “When the ice retreated, it exposed the bottom of the cliff face, allowing that rock material to suddenly collapse into the fjord.”
This insight draws attention to the dual challenge of climate change: while it compels more visitors to explore the natural beauty of Alaska, it also renders these majestic landscapes highly perilous.
Growing Concerns and Calls for Action
Dr Higman expressed profound concern regarding the escalating risk of megatsunamis. “At this point, I’m pretty confident that these are increasing not just a little bit, but increasing a lot,” he asserted. He estimates the frequency of such events has surged by as much as tenfold in recent decades. This alarming trend has prompted calls for enhanced monitoring of vulnerable regions in Alaska to better prepare for future disasters.
In light of these risks, some cruise lines have decided to halt operations into Tracy Arm, acknowledging the safety concerns posed by the unpredictable nature of megatsunamis.
Why it Matters
The recent megatsunami in Alaska is not just a geological curiosity; it underscores a pressing global issue. As climate change accelerates, the stability of mountain ranges and glaciers is increasingly compromised, posing dire risks to both human life and the environment. With more tourists venturing into these breathtaking yet treacherous regions, the need for comprehensive hazard monitoring and disaster preparedness has never been more critical. This incident serves as a wake-up call, urging society to confront the realities of climate change before they manifest in even more catastrophic ways.
