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On August 10, 2023, a small tour boat in Alaska, operated by Christine and Jeffrey Smith, encountered a dramatic and unforeseen geological event while anchored in Ford’s Terror. The couple had eight passengers on board for a multi-day excursion to explore the stunning fjords and glaciers of the region when they witnessed the alarming effects of a landslide that occurred approximately 75 kilometres away in Tracy Arm. This incident highlights the increasing geological risks posed by climate change as glaciers continue to retreat.
Unprecedented Water Surge
At around 6 a.m., Jeffrey Smith observed an unusual surge of foamy water rushing into the inlet where their boat, the David B, was anchored. “It was like a river running across the sandbar,” he recounted, describing the sight as something they had never encountered in two decades of anchoring in the area. Although the boat remained safely moored in deep water, the unusual inflow was disconcerting enough to put both the crew and passengers on high alert.
As the couple monitored the situation, they reached out to a local seismologist and neighbour, Jacqueline Caplan-Auerbach, who confirmed that a landslide had occurred in Tracy Arm, leading to significant water disturbances even far from the event site. The Smiths had initially planned to be in Tracy Arm that day but changed their itinerary due to poor weather conditions. This fortunate decision may have saved their lives.
The Tsunami’s Impact
In the wake of the landslide, a massive tsunami surged through Tracy Arm, reaching heights of up to 480 metres—equivalent to about 85 per cent of the CN Tower in Toronto. The wave displaced water violently, uprooting trees and altering the landscape along the fjord. “Essentially, the side of a mountain collapsed into the fjord,” explained Daniel Shugar, a geomorphologist from the University of Calgary, who led a study published in *Science* that analysed the landslide and tsunami.
The tsunami’s destructive power caught nearby vessels off guard, particularly the National Geographic Venture, which was fortunate to be positioned closer to the entrance of Tracy Arm, thereby avoiding the worst of the waves. Nevertheless, the vessel experienced strong currents and visual disturbances from the churning waters. Further down the fjord, a charter yacht called the Blackwood struggled against the incoming waves, illustrating the widespread impact of the tsunami.
Assessing the Geological Risks
The study has underscored the potential for similar geological events to occur in the future, particularly as climate change accelerates the retreat of glaciers. Over the course of thousands of years, glaciers have carved steep valleys that, as the ice melts, leave the canyon walls vulnerable to collapse. The South Sawyer glacier, in particular, lost significant ice last summer, creating an unstable cliff that ultimately gave way.
Dr. Shugar noted that the situation was exacerbated by the time of year, as summer typically sees increased marine traffic, including cruise ships that could have been caught in the disaster. Remarkably, the relatively low number of vessels affected was seen as a fortunate anomaly rather than the norm. “It isn’t even so much that there could have been people in there, but how incredibly anomalous it was that no one was there,” said Dr. Caplan-Auerbach.
A Call for Monitoring and Awareness
In the aftermath of the event, scientists are advocating for enhanced monitoring of unstable geological formations, especially in areas frequented by tourists. The study suggests that seismic signals may provide an early warning system for impending collapses, as vibrations in the ground increased noticeably hours before the landslide occurred. These insights could prove invaluable for safeguarding individuals and infrastructure in high-risk zones.
Lynn Moorman, a geologist from Mount Royal University, highlighted the need for a deeper understanding of geological hazards in popular tourist locations, noting her own experience on a cruise ship close to the glacier in Tracy Arm just days before the landslide. The incident serves as a stark reminder that as our planet warms, the risks associated with glacier retreat and subsequent geological instability will only grow.
Why it Matters
The Tracy Arm tsunami not only exemplifies the immediate dangers posed by climate change but also highlights the urgent need for comprehensive risk assessment and monitoring in vulnerable regions. With the potential for similar events in the future, especially in popular tourist destinations, it is crucial to prioritise public safety and environmental awareness. As the landscape of our planet continues to evolve, so too must our strategies for understanding and mitigating these natural hazards.
