1 in 5 Alaskan fjords at risk of deadly tsunamis

By VirentaNews Staff — May 10, 2026

Could the retreat of glaciers due to climate change be setting the stage for more catastrophic tsunamis? In remote regions like Alaska, where massive ice sheets have long supported towering mountain walls, scientists are observing a troubling chain reaction: as glaciers melt and recede, the slopes they once braced are collapsing into narrow fjords, triggering powerful, localized tsunamis. These events, once considered rare, may become more frequent as global temperatures rise. The 2015 landslide in Taan Fiord, which generated a tsunami that surged 633 feet—the tallest in recorded history—was a dramatic wake-up call. Now, researchers are racing to understand how widespread this risk is and whether other glaciated regions could face similar threats as the planet warms.

What connects glacial retreat to landslide tsunamis?

Glaciers do more than just store ice—they act as structural supports for steep mountain slopes. As they melt and thin due to rising temperatures, the lateral pressure that once held rock and soil in place diminishes, making slopes increasingly unstable. In Alaska’s steep, glaciated fjords, this loss of support can lead to massive landslides, sometimes involving hundreds of millions of cubic feet of material. When this debris crashes into a narrow inlet of water, it displaces vast quantities of water in seconds, generating a tsunami. Unlike ocean-wide tsunamis caused by undersea earthquakes, these are localized but extremely powerful near the impact zone. According to a 2021 study published in Nature Communications, over 100 Alaskan fjords now face elevated landslide tsunami risks due to recent glacial retreat, a phenomenon scientists call “post-glacial adjustment.”

What evidence shows these events are increasing?

Geological and satellite data reveal a clear trend: as glaciers retreat, landslide frequency in formerly glaciated areas is rising. In Taan Fiord, the 2015 event followed decades of rapid ice loss from the Tyndall Glacier. Researchers from the U.S. Geological Survey used lidar imaging and sediment analysis to confirm that the landslide released about 180 million tons of rock, triggering a wave that stripped vegetation up to 193 meters above sea level. Similar events have been recorded in other parts of Alaska and British Columbia, including a 2020 landslide in Elliot Creek that produced a 100-meter tsunami. A 2023 assessment by the American Association for the Advancement of Science identified 462 previously stable slopes in Alaska now at high risk of failure due to ice loss. These findings suggest that what was once a rare geological curiosity may now be an emerging climate-related hazard.

Are scientists overestimating the risk?

While the link between glacial retreat and slope instability is well-supported, some geologists caution against generalizing the tsunami threat too broadly. They argue that not all deglaciating slopes are prone to catastrophic failure—local geology, rock type, and drainage patterns play critical roles in determining stability. For instance, some fjords in Norway and Patagonia have experienced extensive ice loss without major landslides, suggesting that Alaska’s steep, seismically active terrain may be uniquely vulnerable. Others point out that landslide tsunamis, while devastating locally, rarely threaten distant coastlines like tectonic tsunamis do. Additionally, monitoring these remote areas remains challenging, making it difficult to assess real-time risks or issue warnings. As University of Alaska geophysicist Dr. Erin Pettit noted, “We’re seeing a new hazard emerge, but predicting exactly when and where the next big slide will happen is still more art than science.”

What are the real-world consequences of these tsunamis?

The immediate danger is to remote communities, researchers, and maritime activities near vulnerable fjords. While Alaska’s interior is sparsely populated, cruise ships, fishing vessels, and Indigenous communities often operate in these waters. In 2015, the Taan Fiord tsunami occurred in an uninhabited area, but had it happened near a populated bay, the death toll could have been catastrophic. Emergency planners in Alaska are now working with scientists to map high-risk zones and develop early warning systems using seismic and satellite data. Beyond Alaska, similar risks may exist in Greenland, the Himalayas, and parts of the Andes, where glaciers are also retreating rapidly. In 2017, a landslide tsunami in Greenland’s Karrat Fjord killed four people and destroyed a village, underscoring the global relevance of this threat.

What This Means For You

While you may not live near a glacial fjord, the increasing frequency of climate-driven geological hazards highlights how interconnected Earth’s systems are. As ice melts, it doesn’t just raise sea levels—it reshapes landscapes in unpredictable ways. If you travel to glaciated regions or follow climate risk assessments, understanding these cascading effects is crucial. Governments and scientists must invest in monitoring and hazard planning, especially in vulnerable Arctic and high-mountain regions. The era of stable slopes and predictable coastlines may be ending.

As researchers continue to map unstable slopes and model future risks, one question remains unanswered: which fjord will be next? With hundreds of potentially dangerous sites identified and climate change accelerating, the scientific community faces the urgent task of predicting the unpredictable—before the next wall of water comes crashing down.

Source: The New York Times