Geologists say it would have been impossible for Parks Canada to predict or prevent the massive rockfall that killed two people in Banff National Park on Thursday, with pressure building over many years released as hikers were below.
University of Calgary Prof. Daniel Shugar says water from a lake above the cliff at Bow Glacier Falls had been seeping through rocks for decades and eventually provided enough force to dislodge a boulder, triggering the rockfall.
He says the tragedy involved "a bad confluence of events."
Davide Elmo, a mining engineering professor at the University of British Columbia, says Parks Canada can't predict rockfalls.
He says the only thing officials can do is to tell the public about the risks when they enter an area that might be prone to them.
He says that looking at a rock face from the outside doesn't show what's happening inside and working out exactly when a slide might occur is impossible to calculate.
"Some people might ask Parks Canada, why didn't do you anything about it," said Elmo, who also has a degree in engineering geology and is an expert in rock mechanics.
"Well, that kind of rockfall cannot be stopped."
John J. Clague, an emeritus professor in Earth sciences at Simon Fraser University says that while it's easy to find evidence of rockfalls from the past, predicting where and when they will happen again is difficult.
This report by The Canadian Press was first published June. 20, 2025.
Nono Shen and Fakiha Baig, The Canadian Press
