Imagine what it would be like if every car in Canada were to careen uncontrollably down a mountain, through a narrow corridor and into the ocean.

That含羞草研究社檚 approximately what the mass of rock that fell into Elliot Lake, turning a small creek above Bute Inlet into a raging torrent, equated to, according to a new report from researchers on the November 2020 Bute Inlet landslide. According to the paper, roughly 18 million cubic metres of rock descended 1,000 metres into a glacial lake at the head of Elliot Creek in the traditional territory of the Homalco First Nation north of Campbell River on the B.C. mainland coast. The landslide had a mass of 50 million tonnes 含羞草研究社� equal to the combined mass of every car in the country 含羞草研究社� and caused a 100 metre Tsunami in a small lake, and sent pretty much everything down the valley to the ocean.

含羞草研究社淲e expect large events to happen from time to time in areas like that. What含羞草研究社檚 a little bit unusual though, is the magnitude of the wave. We have seen it in other places too, but I think this is the largest wave we含羞草研究社檝e seen in B.C. We haven含羞草研究社檛 witnessed or seen the effects of anything that has been more than 100 metres high,含羞草研究社� said Marten Geertsema, a researcher with the Ministry of Forests. 含羞草研究社淲hat含羞草研究社檚 really remarkable is if you think about that small valley, you wouldn含羞草研究社檛 be able to outrun this. We lost four million cubic metres of material in that creek in about ten minutes. It eroded to a depth of about 50 metres below the creek bed in a few places. It含羞草研究社檚 hard to imagine that water power.含羞草研究社�

Researchers were quick to head into the valley and collect as much data as possible. Over the past year, they have been compiling and analyzing that data and have recently published their findings.

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Part of Geertsema含羞草研究社檚 research is the effects of climate change on natural hazards. Some of the modelling data presented in the paper can be used to help people prepare for the effects of climate change, particularly as rock slides and rock avalanches tend to increase in the mountains as the glaciers that had formerly held the rocks in place melt away.

含羞草研究社淲e see an increase in rock slides in mountain areas, mainly in under two situations. One is when glaciers are receding, so they含羞草研究社檙e often on the walls above those glaciers or in the area of those glaciers. The other area is where we have mountain permafrost degradation,含羞草研究社� Geerstema said. 含羞草研究社淲e含羞草研究社檙e doing research in that area right now. We含羞草研究社檙e exploring, especially these areas where we think landslides could be more likely to increase 含羞草研究社� along the glacier margins. We含羞草研究社檙e looking for these kinds of deformations that may give us an indication that slopes may be ready to fail.含羞草研究社�

As glaciers melt, they reveal lakes like Elliot Lake that were once hidden beneath ice. The report shows evidence of a similar rockfall in the same area, but since the lake was covered by the glacier at the time there was no catastrophic outburst flood.

含羞草研究社淎n older landslide scar that is visible in aerial photography reveals that a landslide occurred from the same location before the 1950s,含羞草研究社� the report says. 含羞草研究社淭he older landslide likely ran across the glacier before Elliot Lake formed and thus the catastrophic flood experienced during the recent event could not have occurred.含羞草研究社�

Over the past hundred years, over 1,000 similar glacial lake outbursts have been recorded around the world, and over 12,500 people have died as a result. In 2017, an outburst flood in Greenland killed four and washed away most of the fishing village of Nuugaatsiaq.

In Canada, most of the events have been in remote areas that have not caused any injury to people, however, the researchers note that 含羞草研究社渢here is no assurance that this will be true in the future, given increased development and tourism in these formerly remote areas.含羞草研究社�

LiDAR data compiled by the Hakai Institute has allowed researchers to do modelling of the slopes, which can be used to indicate dangerous areas in the mountains.

含羞草研究社淚t was really fortunate that we got LiDAR from before the event and then after,含羞草研究社� Geertsema said. 含羞草研究社淭hat LiDAR was provided by the Hakai Institute, so we含羞草研究社檙e pretty grateful to them.含羞草研究社�

The Southern Coast Mountains of Western Canada has over 8,000 square kilometres of glacier-covered terrain, and it is seeing some of the fastest glacial loss rates in the world.

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