In a startling revelation, a recent study has confirmed that a colossal wave, resulting from a significant landslide in Alaska, ranks as the second tallest megatsunami ever documented. This event, which unfolded in August 2025 near South Sawyer Glacier, serves as a stark reminder of the escalating dangers associated with melting glaciers and the geological instability they can cause.
The Catastrophic Event
Last summer, a massive wave surged through a secluded fjord in southeast Alaska, leaving devastation behind. While the event went largely unnoticed at the time, a comprehensive analysis has since identified it as a product of a landslide that unleashed approximately 64 million cubic metres of rock—equivalent to the weight of 24 Great Pyramids—into the waters below. The impact generated a wave that reached nearly 500 metres in height, a phenomenon rarely seen in recorded history.
Dr. Bretwood Higman, a geologist who surveyed the aftermath at Tracy Arm Fjord, remarked on the near-miss with tourist cruise ships that could have been caught in the tumult. “It was a close call,” he noted, expressing concern that future incidents may not afford such luck. “We know that there were people that were very nearly in the wrong place,” he added, underscoring the precarious nature of these geological events.
Understanding Megatsunamis
Megatsunamis, distinct from their oceanic counterparts triggered by seismic activity, occur when a massive rock slide plunges into water, creating localized waves that dissipate rapidly. In contrast, traditional tsunamis can traverse vast ocean distances, instigated by underwater earthquakes or volcanic activity, as exemplified by the catastrophic 2011 tsunami in Japan.
The most significant recorded megatsunami occurred in the 1950s, measuring over 500 metres. The recent Alaskan event now stands as a stark second, reinforcing the unpredictable nature of geological risks in the region.
Climate Change and Increased Vulnerability
The implications of climate change are increasingly pertinent, with new research published in the journal *Science* indicating that glacier melt exacerbates the likelihood of such collapses. Dr. Stephen Hicks of University College London explained that the retreating glaciers, which previously stabilised the rock formations, now expose cliff faces to erosion and destabilisation. “When the ice retreated, it allowed that rock material to suddenly collapse into the fjord,” he stated, illustrating the interconnectedness of climate change and geological hazards.
Alaska’s unique topography—characterised by steep mountains and narrow fjords—coupled with frequent seismic activity, renders it particularly susceptible to megatsunamis. As tourism in these remote areas increases, particularly with cruise ships aiming to showcase the region’s natural beauty, the risks associated with these geological phenomena cannot be ignored.
Calls for Enhanced Monitoring
In light of the alarming findings, experts are advocating for improved monitoring of regions in Alaska prone to megatsunamis. Dr. Higman emphasises the urgent need for vigilance, stating, “At this point, I’m pretty confident that these are increasing not just a little bit, but a lot—maybe in the order of ten times as frequent as they were just a few decades ago.”
In response to safety concerns, several cruise companies have made the decision to cease operations in Tracy Arm, reflecting a growing awareness of the potential dangers.
Why it Matters
The recent megatsunami in Alaska serves as a critical wake-up call, not only highlighting the immediate geological risks posed by climate change but also underlining the urgent need for proactive measures in monitoring and preparedness. As more individuals seek to explore the breathtaking landscapes of Alaska, the intersection of tourism and nature’s unpredictability demands a reassessment of safety protocols and environmental stewardship. The implications extend beyond the region, emphasising a global responsibility to understand and mitigate the impacts of climate change on our natural world.