A colossal megatsunami triggered by a landslide in Alaska last summer has emerged as the second tallest wave ever recorded, underscoring the alarming consequences of melting glaciers and the increasing risks they pose. This event, which devastated a remote fjord in Southeast Alaska, has only recently come to light following a detailed scientific investigation.
A Catastrophic Event Unfolds
In the early hours of August 2025, a staggering 64 million cubic metres of rock—equivalent to 24 Great Pyramids—plummeted into the waters of a remote fjord, creating a wave that reached nearly 500 metres in height. The incident, which went largely unnoticed at the time, wreaked havoc in the Tracy Arm Fjord, an area frequented by cruise ships. Thankfully, the timing of the event spared tourists from the disaster, a fact highlighted by Dr Bretwood Higman, a geologist who witnessed the aftermath firsthand. “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 are typically the result of massive landslides triggered by geological events such as earthquakes or the destabilisation of loose rock. Unlike traditional tsunamis, which can traverse vast oceanic distances following undersea earthquakes, megatsunamis are generally localised phenomena that dissipate quickly. The record for the largest megatsunami dates back to the 1950s, surpassing 500 metres.
Dr Higman, who arrived at the scene weeks after the disaster, found a landscape transformed: uprooted trees scattered across the mountainside and extensive areas of rock stripped bare of soil and vegetation. Alaska’s unique geography, characterised by steep mountains and narrow fjords, combined with frequent seismic activity, makes it particularly susceptible to these massive waves.
The Impact of Climate Change
Recent research published in the journal *Science* has drawn a direct connection between climate change and the increasing frequency of such hazardous events. As glaciers melt due to rising temperatures, they undermine the stability of surrounding rock formations. Dr Stephen Hicks from University College London noted that the retreating ice previously acted as a stabilising force, and its absence allows rock to collapse more readily into the fjord below.
“Our studies indicate that these events are not just becoming more frequent but are increasing significantly,” he stated. “The risks of megatsunamis are rising, potentially by an order of ten times compared to just a few decades ago.” This alarming trend poses a grave threat to the burgeoning tourism industry in these remote areas, as more people venture into the region to witness its natural beauty while unknowingly placing themselves at risk.
Calls for Increased Monitoring
In light of these findings, scientists are advocating for enhanced monitoring of hazardous areas in Alaska that are vulnerable to megatsunamis. Some cruise operators have already decided to halt voyages into Tracy Arm, citing safety concerns for their passengers.
As the climate continues to change, researchers warn that the likelihood of similar catastrophic events is set to rise, with potentially devastating consequences for both human life and the environment.
Why it Matters
The recent megatsunami in Alaska serves as a stark reminder of the unpredictable and escalating dangers posed by our changing climate. It highlights the urgent need for comprehensive monitoring and risk assessment in vulnerable regions, especially as tourism to these breathtaking yet perilous landscapes increases. As we confront the realities of climate change, understanding and mitigating these risks will be crucial in safeguarding both lives and livelihoods in the years ahead.