In an alarming revelation, scientists have confirmed that a colossal megatsunami triggered by a significant landslide in Alaska last summer stands as the second largest wave ever recorded. This event, which unleashed a towering wave nearly 500 metres high, underscores the escalating dangers posed by climate change-induced glacier melting. The tsunami, which wreaked havoc in a remote fjord, went largely unnoticed at the time, but new research brings to light its profound implications.
The Destructive Event
Last August, a massive landslide—estimated to involve 64 million cubic metres of rock, equivalent to 24 Great Pyramids—plummeted into the icy waters of Tracy Arm Fjord. The sheer force of this geological collapse generated a wave of unprecedented height, sweeping through the fjord with devastating power. Had the landslide occurred during peak tourist hours, it could have resulted in catastrophic consequences for cruise ships navigating the area. Dr Bretwood Higman, a geologist from Alaska who surveyed the aftermath, described the incident as “a close call,” noting, “We know that there were people that were very nearly in the wrong place.”
The Mechanics of Megatsunamis
Megatsunamis differ from traditional tsunamis, which are often generated by seismic activity in the ocean. Instead, these giant waves result from landslides—either triggered by earthquakes or the destabilisation of loose rock—collapsing into water. They typically remain localised and dissipate rapidly. The largest recorded megatsunami occurred in the 1950s, measuring over 500 metres in height, making this latest event a significant scientific concern.
Dr Higman, who visited the affected site shortly after the tsunami, reported a landscape marred by destruction: uprooted trees scattered across the mountainside, vast areas stripped of soil and vegetation, and a stark reminder of nature’s power.
Climate Change and Increasing Risks
Alaska’s topography—a combination of steep mountains, narrow fjords, and frequent seismic activity—renders it particularly susceptible to megatsunamis. Recent research published in the journal Science indicates that climate change is exacerbating the situation. As glaciers recede, they no longer provide the structural support necessary to stabilise the rock formations above. Dr Stephen Hicks from University College London explained that the melting glaciers previously “helped to hold up this piece of rock,” and their retreat has exposed cliff faces, leading to increased risks of collapse into the fjord.
The implications are dire. “More people are now going to remote areas,” Dr Hicks warned, referring to the growing number of tourists attracted to the natural beauty of Alaska. However, he cautioned, these remote locations can also be perilous.
Calls for Enhanced Monitoring
Dr Higman expressed concern about the rising frequency of such events, suggesting that megatsunamis may now be occurring “maybe in the order of 10 times as frequent as they were just a few decades ago.” In light of this growing threat, scientists are advocating for enhanced monitoring of vulnerable areas in Alaska. Some cruise lines have already made the decision to halt operations in Tracy Arm, prioritising passenger safety amid these heightened risks.
Why it Matters
The emergence of this colossal megatsunami serves as a stark reminder of the interconnectedness of climate change, geological phenomena, and human activity. As glaciers continue to melt at alarming rates, the likelihood of devastating events like this increases, posing significant risks not only to local wildlife and ecosystems but also to unsuspecting tourists. With more people venturing into these stunning yet dangerous landscapes, it is crucial to take proactive measures to safeguard lives and monitor geological shifts that could lead to future disasters. The urgency of this situation cannot be overstated; as we continue to grapple with the ramifications of climate change, understanding and preparing for its consequences is more vital than ever.