The Frank Slide was one of the largest & deadliest landslides in Canadian history, where 82 million tonnes (90 million tons) of limestone collapsed from Turtle Mountain & descended upon Frank, Alberta. The town of Frank was founded a coal mining town on September 10, 1901. At 4:10am on April 29, 1903, a section of the summit of Turtle Mountain about 1,000 metres across broke off, travelling down the mountainside at a rate of 112km/hr (70mph) before cascading upwards on the opposite side. Prior to that it had long been known by First Nations as "the mountain that moves", refusing to live anywhere near it. There were also reports about constant rockfalls & slides. About 100 people lived in the path of the slide, mostly on the outskirts, & it is estimated that about 70-90 lives were lost. Most of their bodies remain entombed w/in the slide, about 12 skeletons were located in the immediate aftermath & six more were unearthed during the construction of the Crowsnest Highway in 1924. About 17 miners who were working the coal seams under Turtle Mountain became trapped when the slide caved their main portal, & the slide had dammed the neaby river which caused water to start seeping through a caved second portal into the mine. One miner knew the coal seam extended upwards to the surface so they worked up the coal seam until the toxic air started to weaken them. By then three last miners continued digging until they broke through the surface, able to tunnel themselves out after 13 hours underground. While the main part of the town of Frank was spared, it grew in size later on to the mining boom before slowing down to the current time. Now today there is an interpretive center & trail as the slide remains largely unchanged. You can see that some of the boulders here are massive. About 80 monitoring stations have also been placed on Turtle Mountain as scientists are aware that another slide of smaller scale is likely imminent one day, perhaps from the south peak to the right of the slide in this view. A few kilometres away is the Hillcrest Mine memorial, site of Canada's deadliest mining disaster in 1914.
More info here: https://en.wikipedia.org/wiki/Frank_Slide
The Rocky Mountains (or Rockies) are a major mountain range in western North America. The Rocky Mountains stretch more than 4,800 kilometres (2,980 mi) from the northernmost part of British Columbia, in Canada, to New Mexico, in the United States. The range's highest peak is Mount Elbert in Colorado at 14,440 feet (4,401 m) above sea level. Though part of North America's Pacific Cordillera, the Rockies are distinct from the Pacific Coast Ranges (as named in Canada) or Pacific Mountain System (as known in the United States), which are located immediately adjacent to the Pacific coast.The eastern edge of the Rockies rises impressively above the Interior Plains of central North America, including the Front Range of Colorado, the Wind River Range and Big Horn Mountains of Wyoming, the Absaroka-Beartooth ranges and Rocky Mountain Front of Montana, and the Clark Range of Alberta. In Canada geographers define three main groups of ranges: the Continental Ranges, Hart Ranges and Muskwa Ranges (the latter two flank the Peace River, the only river to pierce the Rockies, and are collectively referred to as the Northern Rockies). Mount Robson in British Columbia, at 3,954 metres (12,972 ft), is the highest peak in the Canadian Rockies. The Muskwa and Hart Ranges together comprise what is known as the Northern Rockies (the Mackenzie Mountains north of the Liard River are sometimes referred to as being part of the Rockies but this is an unofficial designation).The western edge of the Rockies includes subranges such as the Wasatch near Salt Lake City and the Bitterroots along the Idaho-Montana border. The Great Basin and Columbia River Plateau separate these subranges from distinct ranges further to the west, most prominent among which are the Sierra Nevada, Cascade Range and Coast Mountains. The Rockies do not extend into the Yukon or Alaska, or into central British Columbia, where the Rocky Mountain System (but not the Rocky Mountains) includes the Columbia Mountains, the southward extension of which is considered part of the Rockies in the United States. The Rocky Mountain System within the United States is a United States physiographic region; the Rocky Mountain System is known in Canada as the Eastern System.