A colossal megatsunami triggered by a landslide in Alaska’s fjord system has emerged as the second tallest wave ever recorded, underscoring the growing dangers associated with climate change and glacier retreat. This significant event, which transpired in August 2025, has drawn renewed attention from the scientific community, highlighting the catastrophic potential of such geological phenomena in a warming world.
The Event and Its Impact
In August 2025, a massive landslide involving approximately 64 million cubic metres of rock—equivalent to the volume of 24 Great Pyramids—plunged into the waters of Tracy Arm Fjord, resulting in a wave that reached an astonishing height of nearly 500 metres. The sheer force of this natural disaster wreaked havoc across the remote region, but it remained largely unreported at the time. Fortunately, the incident occurred in the early hours, sparing tourist cruise ships from being caught in its destructive path.
Dr. Bretwood Higman, a geologist based in Alaska, inspected the aftermath and noted the severe damage. He remarked, “It was a close call,” emphasising that the incident could have resulted in a tragic loss of life had circumstances been different. The devastation included uprooted trees and extensive scarring of the mountainside, revealing the scale of the disaster.
Understanding Megatsunamis
Megatsunamis are typically generated by landslides caused by geological disturbances such as earthquakes or the destabilisation of loose rock. Unlike oceanic tsunamis, which can travel vast distances and wreak havoc on coastal regions following seismic events, megatsunamis are generally localized and dissipate relatively quickly.
The largest recorded megatsunami occurred in the 1950s and surpassed 500 metres in height. The recent event in Alaska, though the second largest, serves as a stark reminder of the potential for future disasters in vulnerable regions.
The Role of Climate Change
Recent research published in the journal *Science* indicates that climate change is exacerbating the frequency and severity of such landslides. As glaciers melt, they no longer provide crucial support to the underlying rock formations. Dr. Stephen Hicks from University College London explained that as the ice retreats, it exposes cliff faces, leading to increased rock collapses into the fjord below.
Hicks, along with his research team, has expressed concerns over the future risks posed by megatsunamis, particularly as more tourists venture into these remote and picturesque areas. “More people are now going to remote areas—often these tourist cruises are visiting to witness the natural beauty and learn about climate change—but they are also entering dangerous territories,” he cautioned.
Heightened Risk and Future Monitoring
Dr. Higman conveyed a sense of urgency regarding the increasing risks associated with megatsunamis, stating, “I’m pretty confident that these events are becoming ten times more frequent than they were just a few decades ago.” This alarming trend calls for enhanced monitoring of geological hazards in Alaska and other at-risk locations.
In response to these findings, some cruise companies have decided to halt operations in Tracy Arm, prioritising passenger safety. This decision reflects a growing awareness of the potential threats posed by the dynamic and unpredictable nature of the region’s geology.
Why it Matters
The recent megatsunami serves as a critical wake-up call regarding the interplay between climate change and geological hazards. As our planet warms, the stability of these natural landscapes is increasingly compromised, leading to more frequent and severe geological events. The implications extend beyond scientific interest; they pose real threats to human safety, particularly in regions that attract tourism. It is imperative that we take these warnings seriously, implementing better monitoring systems and preparedness measures to safeguard vulnerable communities in the face of an uncertain future.
