Described as a rare “waterfall of danger”, the tsunami then sent a huge torrent of water or “flood outbreak” to Elliot Creek, uprooting trees, soil and rocks as it fell into the valley. The slurry in turn was diverted to the Southgate River and then to the Bute Inlet, leaving a ruined landscape in its path. “Imagine a landslide with a mass equal to that of all cars in Canada, traveling at a speed of about 140 kilometers per hour when it falls into a large lake,” said lead author Marten Geertsema, an assistant professor of ecosystem science at UNBC. “The landslide displaced enough water to cause a tsunami with a wave height of more than 100 meters. This drained most of the lake water which then traveled to a 10-kilometer canal causing extensive erosion of the canal and loss of salmon habitats. ” According to the study, the torrent destroyed 8.5 kilometers of salmon spawning and sent a column of sediment and organic matter 60 kilometers to the Bute entrance. A huge landslide on the remote central coast of BC. caused a tsunami in the lake more than 100 meters high, sending an “explosion flood” to Elliot Creek – uprooting trees, soil and rocks – which was then diverted to the Southgate River and then to Bute Inlet. (CBC)
The rapid thinning and retreat of the glacier at the site of the landslide set the stage for the dangerous waterfall, according to the study co-author. “Once you lose the ice support structure that supports and protects these steep slopes, they are much more prone to failure,” said UNBC geography professor Brian Menounos. The slide recorded the equivalent of a 5.0 magnitude earthquake and was first detected by someone at Columbia University in the US who was monitoring seismic signals. Although scientists knew the general area where it happened, it was just a Vancouver island helicopter pilot began to hang about the wreckage at Bute Inlet and the destruction of the Southgate River and Elliot Creek, which managed to zero in on the exact point of the slide and a large scar on a mountain from where it all started. The landslide hit the Elliot Creek riverbed, creating this gorge, after an initial outflow into a glacial lake caused a flood. (Bastian Fleury / 49 North Helicopters)
With the climate continuing to warm and glacier melting accelerating, Menounos said the research would provide a better understanding of the potential for similar events. “If you look at other steep areas in British Columbia, we know that glaciers will continue to recede, exposing these steep slopes,” he said. “If such a situation occurs in a more densely populated corridor, the Squamish Valley, for example, and the Sea-to-Sky, then you will begin to have these consequences that will directly affect people.” The landslide, tsunami and flood occurred in the area of ​​Homalco First Nation. It is not known if anyone was injured or killed. Menounos said the involvement of Homalco First Nation members was crucial to the research. “It’s a really proud moment,” Menounos said. “It is incredibly important that we co-create knowledge in the future. It is their country and we are very proud to work directly with them.”