This phenomenon, observed mainly in Alaska and British Columbia, is increasingly linked to the impacts of climate change on mountain glaciers.
Lake tsunamis, often triggered by landslides that plunge into small, isolated bodies of water, usually occur far from populated regions.
However, Bretwood Higman, a geologist at Ground Truth Alaska, emphasizes the growing risk of these events reaching more densely populated areas. There are significant tsunami risks near bodies of water such as Portage Lake near Whittier, Eklutna, Seward, Valdez and Juneau, Grewingk Lake in Kachemak Bay State Park and Index Lake near Glacier View.
Quoted by Earth.com, Higman stressed the importance of monitoring areas prone to lake tsunamis. The expert pointed out that certain seismic signals, which can precede catastrophic landslides by days, can be key to early detection if properly understood.
Labeled as an emerging climate-related hazard, tsunamis in lakes are fostered by geological conditions that are becoming more common due to climate change.
Not only does the melting of glaciers weaken the structural integrity of adjacent valley walls, increasing their likelihood of collapse, but warming conditions also degrade the permafrost that helps stabilize mountain slopes.
The recent increase in these phenomena was evidenced by the 2020 Elliot Creek tsunami in British Columbia. This landslide displaced 18 million cubic meters of material, causing tsunami waves over 100 meters high that devastated local ecosystems.
Lake tsunamis, also known as seiches, are distinct from oceanic tsunamis. While oceanic tsunamis are often triggered by earthquakes, volcanic eruptions or underwater landslides, lake tsunamis can result from sudden atmospheric changes, strong winds or the rapid movement of water by landslides or other major disturbances. These disturbances push the water from one end of the lake to the other, creating waves that can oscillate back and forth until they stabilize.
Historical cases, such as the seiche of Lake Michigan in 1954, underline the potential impact on human settlements. Although these phenomena are less common and generally less destructive than oceanic tsunamis, the risk to communities near vulnerable bodies of water remains significant.
