A recently uncovered analysis reveals that a colossal megatsunami in Alaska last summer stands as the second highest wave ever recorded, offering a sobering glimpse into the dangers posed by our changing climate. Triggered by a landslide in the remote fjords of Southeast Alaska, this event serves as a stark reminder of the potential risks associated with melting glaciers and the increasing frequency of geological hazards.
A Natural Catastrophe Unveiled
The megatsunami, which occurred in August 2025, unleashed a wave that reached nearly 500 metres in height after an astounding 64 million cubic metres of rock—equivalent to the weight of 24 Great Pyramids—plummeted into the ocean. This remarkable event took place in the early hours of the morning, inadvertently sparing tourist cruise ships that might have otherwise faced catastrophe.
Dr. Bretwood Higman, a geologist from Alaska who witnessed the aftermath at Tracy Arm Fjord, noted the potential for disaster. “It was a close call,” he remarked. “We know that there were people who 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 more commonly known counterparts, are generated by massive landslides, typically triggered by earthquakes or the destabilisation of loose rock. These waves are usually confined to local areas, dissipating rapidly, whereas traditional tsunamis can traverse vast ocean distances, leading to widespread destruction, as witnessed during the catastrophic 2011 Japan tsunami.
Historically, the largest recorded megatsunami occurred in the 1950s and surpassed 500 metres in height. The megatsunami in question now ranks as the second highest ever documented, raising concerns about the growing frequency of such occurrences in Alaska.
The Role of Climate Change
Recent research published in *Science* delves into the environmental factors exacerbating these geological events. The study indicates that climate change-driven glacier melt is significantly heightening the risk of landslides and subsequent megatsunamis. Dr. Stephen Hicks from University College London explained, “The glacier was previously helping to hold up this piece of rock. When the ice retreated, it exposed the bottom of the cliff face, allowing that rock material to suddenly collapse into the fjord.”
This research highlights the delicate balance between glacial stability and geological hazards, emphasising that as glaciers recede, the risks associated with landslides and megatsunamis will only escalate.
The Implications for Tourism and Safety
As tourism in Alaska continues to grow, more visitors are drawn to the stunning natural beauty of areas like Tracy Arm Fjord, often with the intention of learning about climate change. However, this influx raises serious safety concerns, as Dr. Higman warns of the increasing dangers for unsuspecting tourists. “More people are now going to remote areas,” he stated. “These tourist cruises are going to see the natural beauty of the area, but they are also dangerous places to be.”
In response to the heightened risks, some cruise companies have decided to halt trips into Tracy Arm, prioritising passenger safety amid growing apprehension about potential geological hazards.
Why it Matters
The alarming megatsunami in Alaska serves as a critical wake-up call regarding the intersections of climate change, geological instability, and human activity. As our planet continues to warm and glaciers retreat, the frequency of such devastating events is likely to increase, jeopardising both natural ecosystems and human safety. It’s imperative that we take these warnings seriously, implement robust monitoring systems, and prepare for the challenges that lie ahead in an increasingly volatile world.
