 The Frank Slide was a <unk> that buried part of the mining town of Frank , Alberta , Canada . The province of Alberta was not created until September 1905 , more than two years after the slide . The community was still part of the Northwest Territories when the incident occurred at 4 : 10 am on April 29 , 1903 . Over 82 million tonnes ( 90 million tons ) of limestone rock <unk> down Turtle Mountain within 100 seconds , <unk> the eastern edge of Frank , the Canadian Pacific Railway line and the coal mine . It was one of the largest landslides in Canadian history and remains the deadliest , as between 70 and 90 of the town 's residents were killed , most of whom remain buried in the rubble . Multiple factors led to the slide : Turtle Mountain 's formation left it in a constant state of instability . Coal mining operations may have weakened the mountain 's internal structure , as did a wet winter and cold snap on the night of the disaster . 
