A staggering natural phenomenon in Alaska has revealed the chilling implications of climate change as a recent megatsunami—a colossal wave triggered by a landslide—has been identified as the second largest on record. Occurring last summer, this extraordinary event underscores the growing dangers posed by receding glaciers and the geological instability they engender.
The Catastrophic Event: What Happened?
In August 2025, a monumental landslide occurred near South Sawyer Glacier, sending a shocking 64 million cubic metres of rock tumbling into a remote fjord in southeast Alaska. This immense volume, comparable to 24 Great Pyramids, plunged into the water within a matter of seconds, generating a wave that soared to nearly 500 metres. While the disaster unfolded in the early hours, sparing tourist vessels from its wrath, the incident serves as a stark reminder of the risks lurking in this stunning yet perilous landscape.
Alaskan geologist Dr. Bretwood Higman, who surveyed the aftermath, described the scene as one of devastation. “We know that there were people that were very nearly in the wrong place,” he stated, expressing concern about future occurrences. “I’m quite terrified that we’re not going to be so lucky in the future.”
Understanding Megatsunamis and Their Causes
Megatsunamis differ from their more familiar counterparts in that they typically arise from landslides, often triggered by earthquakes or the instability of loose rock. Unlike traditional tsunamis, which can travel vast distances across oceans and wreak havoc on coastal communities, megatsunamis are generally localised, dissipating more quickly but causing immediate and catastrophic damage.
Historically, the most significant megatsunami recorded occurred in the 1950s, reaching heights exceeding 500 metres. This recent event, however, has garnered attention for being the second largest ever documented, raising alarm bells among scientists and safety experts alike.
The Role of Climate Change
New research published in the journal *Science* highlights the alarming connection between glacier melt due to climate change and the risk of such landslides. As glaciers retreat, they no longer provide structural support for rocky cliffs, increasing the likelihood of collapses into the fjords below. Dr. Stephen Hicks from University College London explained that the melting glaciers previously helped to stabilise the rock, and their retreat has exposed precarious cliff faces to collapse.
“Our studies indicate that these landslides are becoming more frequent,” Dr. Higman warned. “I’m pretty confident that these are increasing not just a little bit, but increasing a lot—maybe ten times as frequent as they were just a few decades ago.”
A Call for Vigilance and Safety
The implications of this research are profound, particularly for the burgeoning tourism industry in Alaska. Many cruise companies have now opted to reroute their vessels away from Tracy Arm, acknowledging the heightened risks posed by these natural events. The combination of breathtaking scenery and the potential for sudden geological disasters creates a precarious situation for visitors eager to learn about climate change while enjoying the natural beauty of the region.
Scientists are urging for enhanced monitoring of at-risk areas to better understand and respond to the threats posed by megatsunamis. The precarious dance between nature and human activity in these fragile environments necessitates a careful and informed approach.
Why it Matters
The recent megatsunami in Alaska is not merely a geological curiosity; it serves as a dire warning about the escalating effects of climate change on our planet. As glaciers continue to melt and natural landscapes shift, we must remain vigilant about the potential for catastrophic events that can occur with little warning. This incident compels us to reconsider our relationship with nature, urging us to prioritise safety and sustainability in the face of increasingly volatile environmental conditions. The future of our coastal communities may depend on it.