The tsunami that devastated Alaska in October 2015 happened because of a glacial retreat and scientists warned that it could happen again.
Three years ago, a slope of the Tyndall Glacier collapsed, sending 180 million tonnes of rock into the neighboring fjord that caused a tsunami reaching an elevation as high as 193 meters. It is said to be one of the highest tsunamis recorded in the past century.
Fortunately, Icy Bay, the area that was hit by the water at the time, was uninhabited so no one was harmed. However, if a similar event happens to a populated area, it would be catastrophic.
Experts are warning that the tsunami, which sent waves as high as Seattle's Space Needle, will be a normal occurrence in the future because of climate change.
A team of researchers collected data from the site of the extreme tsunami to assess how serious it had been. The data was published in the journal Nature.
The 2015 Alaskan Tsunami
Tyndall Glacier retreated backward to up to 17 kilometers because of the rapid warming of the climate over the past half-century. Over 400 meters of ice thinning had occurred between 1961 and 1991 before the glacier settled into its current location.
Then, in 2015, a landslide happened. Because there no longer was glacial ice supporting steep slopes, and with the thawing of permafrost, the massive rocks fell and created the gigantic wave that traveled up to as fast as 60 miles per hour.
"Tsunamis triggered by landslide impact can have an order of magnitude shorter periods and higher runups than those driven by tectonics that have dominated tsunami hazard research in recent years," the researchers wrote in their study.
The biggest tsunami ever recorded was in Lituya Bay, also in Alaska in 1958. The event was triggered by a similar landslide that hit the terminus of a glacier and went into the fjord. The wave reached 534 meters and had a period of about 76 seconds.
More Monster Tsunami
Unfortunately, events like the 2015 tsunami in Alaska will happen more frequently if the planet continues to heat up, shrinking glaciers and thawing permafrost. Landslides can produce massive waves as bodies of water continue to rise and move inward to land.
"As the mountain slopes adjust to the new conditions, they may release single rocks, rock avalanches or fail entirely," shared Martin Lüthi, a geographer who documented a smaller tsunami in a fjord in Greenland. "Several very big landslides have happened in areas of rapid deglaciation worldwide, and triggered big tsunami waves when they reached lakes or fjords."
The authors of the study propose to assess potential failure and create a map of areas at risk in order to reduce damage in case a landslide and a tsunami occur in the future.
