A gigantic wave nearly 500 meters high swept through a remote fjord southeast of Alasca last summer. The megatsunami, caused by the collapse of a mountain in the region of Tracy Arm, is only the second largest ever documented by science. Incríveis 64 million cubic meters of rock fell into the water in less than a minute, generating devastating destruction that only did not result in a human tragedy because the event occurred in the early hours of the morning.
The landslide that caused the giant wave went practically unnoticed when it happened. A detailed scientific analysis, however, revealed the true dimension of the phenomenon: 482 meters high, surpassed only by the megatsunami of Baía and Lituya, which occurred in 1958, which reached 524 meters in Alasca.
Estrutura of the event and immediate consequences
The Dr. Bretwood Higman, a geologist who visited the site weeks after the tsunami, found clear evidence of the wave’s devastating force. Entire Árvores were ripped off and thrown into the water. Vastas expanses of scarred rock cover the slopes, devoid of soil and vegetation. The fjord of Tracy Arm, a popular destination for cruise ships exploring the natural beauty of Alasca, was marked by destruction.
Higman described the scenario as frightening. “We know that there were people who came very close to being in the wrong place,” he said. “I’m quite terrified that we won’t be as lucky in the future.” The timing of the event, occurring during the early hours of the morning, prevented tourist ships from being hit by the devastating wave.
Megatsunamis differ from conventional tsunamis by their origin:
- Megatsunamis: caused by earthquake-triggered landslides or loose rocks that hit the water and usually remain localized and dissipate quickly
- Tsunamis in open sea: triggered directly by earthquakes or underwater volcanoes, can travel thousands of kilometers and reach densely populated areas
- Historical Tsunamis: the 2011 tsunami in Japão (Tohoku) produced a 40.5 meter wave; eruption of the Hunga Tonga volcano in 2022 generated a 90-meter wave
Derretimento of glaciers amplifies risk of collapse
Pesquisa published in the magazine Science points out that climate change is accelerating these catastrophic phenomena. The Dr. Stephen Hicks of University College London explained the mechanism: glaciers that once “helped support chunks of rock” have retreated, exposing the base of the cliffs and allowing rocky material to suddenly collapse into the fjord.
The team of researchers combined fieldwork, seismic and satellite data to reconstruct the sequence of events. The collapse involved 64 million cubic meters of rock — equivalent to the volume of 24 Grandes Pirâmides of Egito — plunging into the fjord in record time.
Alasca is particularly vulnerable to megatsunamis. Montanhas Steep, narrow fjords and frequent earthquakes create ideal conditions for these phenomena. The region faces an exponential increase in risk: according to Higman, megatsunamis may be occurring about 10 times more frequently than a few decades ago.
Aumento tourism in risk areas and security measures
Crescente number of people travel to remote Alasca regions, often on cruise ships designed to appreciate natural beauty and understand climate change. Hicks highlighted the contradiction: “These cruises aim to enjoy the region’s natural beauty and learn about climate change, but these places are also dangerous.”
Companhias cruise already react to the event. Algumas announced suspension of operations on Tracy Arm due to passenger safety concerns. The decision reflects recognition that megatsunamis represent a real and growing threat.
Cientistas requests broader monitoring of risks in parts of Alasca considered vulnerable. Recent history — including megatsunami at Fiorde, Dickson, Groenlândia in 2024, 200 meters high — reinforces the urgency for intensified surveillance. The Dr. Higman expressed confidence that incident numbers are increasing not gradually, but dramatically, requiring immediate attention from authorities and tour operators.
