20-06-2025
How does a rockslide happen? 'The mountain that moves' was Canada's deadliest
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First Nations people in the area had noticed instability in the mountain decades earlier and even had a name for it that translated to 'the mountain that moves.' The geological structure of Turtle Mountain was said to be the primary cause of Frank Slide, but weather impacts and coal mining were also noted as factors in the deadly rockslide.
An interpretive centre in Frank now tells the story of the slide and history of the area.
Other Canadian rockslides of note include the 1841 rockfall in the Lower Town of Quebec City, killing 32 people and crushing eight homes, and the 1889 rockslide in the same area that killed more than 40, says the Canadian Encyclopedia.
The worst rockslide worldwide was the Haiyuan Landslides of 1920 in China, when more than 200,000 people were killed. An earthquake caused those landslides.
When did the earliest rockslides in Alberta and B.C. occur?
The 680-tonne Big Rock, a type of quartzite, is an intriguing tourist attraction at Rocky Mountain House in Alberta, but how did this boulder measuring 9.7 metres by 9.4 metres by 5.5 metres get there? Well, the Rocky Mountain House Mountaineer reported the following 11 years back: 'Right around 20,000 years ago the Late Wisconsinan Glaciation was at its height; it was a glacier that could have been one kilometre thick. We know that all of the rocks in the Foothills Erratic Train come from the upper Athabasca drainage area south of Jasper,' said author and geologist Ben Gadd.
