Since that day, the area has been closed to the public and a $85,000 geotechnical assessment has been completed by BCG Engineering.
Pam Clark, visitor experience manager for Jasper National Park, said the initial assessment looked at what happened, what the current risks are and how those risks can be reduced.
She noted the assessment shows that if the event had happened earlier or later in the season, the water levels in Cavell Tarn—the lake beneath the glacier—would have been lower, reducing the amount of flooding after Ghost’s fall.
“The lake was at its highest,” she said. “It was high water, so that contributed to the flooding.”
And it was the flooding—which resulted from the glacier landing in the lake—that caused the greatest damage, washing out the parking lot, picnic area and parts of the lower Path of the Glacier trail.
Clark said despite the damage, the assessment shows the risk of a fall of the same magnitude is low—as only 30 per cent of Ghost remains—so the area will be open to visitors on schedule this year, following a few minor repairs.
Parks plans to open the area in late May or early June after the road has been fixed and some barriers have been put in place, making the area safe for visitors.
“There are safe areas at Cavell where people can, if they read the signs and make good decisions, enjoy that environment without putting themselves at risk,” said Clark.
“I think it’s going to be an attraction for a bit, especially the day we open,” she said. “Normally on opening day we don’t get a lot of vehicle traffic, but I expect this opening day we’ll probably have a full parking lot.”
When people arrive, they’ll notice the new channels that were created by the flooding and the eroding of the picnic area and lower Path of the Glacier Trail—both of which will remain closed for the season.
There will also be a different view, with Ghost no longer dangling from the north face of Mount Edith Cavell.
Clark said JNP’s concern this season is with how the area gets used now that the gentler lower Path of the Glacier trail is closed off, leaving only the upper path, which includes steeper terrain that might not be suitable for all visitors.
Parks staff will be monitoring people’s usage to see what improvements can be made in the future to reduce congestion on the trail.
BCG Engineering is preparing a second assessment outlining risk mitigation options for the area. Clark said once that assessment is complete, Parks will look at how to repair, rebuild and monitor the area to ensure visitor satisfaction and safety.
“We’re counting on some funding for it,” said Clark of the repairs. “We’re still confident, though, in the short term measures we can put in place with our existing [budget].”
Why glaciers fall
Brian Luckman has been monitoring glaciers in Jasper National Park since the mid 1970s.
Of Ghost Glacier—one of his ongoing research subjects—the Western University professor said matter of factly, “Ultimately, it was going to come down at sometime or another.
“The reason it would fall,” he continued, “it would fall once it lost sufficient coherence with the back wall.”
That break from the rock face could be caused by one of two things, said Martin Sharp, a glaciologist and professor at the University of Alberta.
One is a build up of thick ice combined with the stress of gravity. Those two factors cause a glacier to move down the mountain, he said.
“And ultimately [the glacier] might reach a change in gradient and as it goes over that, the increase in the slope also increases the stress on it and that can make it unstable and the whole thing will just fail,” he said, noting that this is a cyclical cycle for some glaciers.
The second possibility is that the glacier melts, putting water between it and the rock, or—during an unusually warm summer—water from the surface gets to the bottom of the glacier. In both cases, the water lubricates the bottom of the glacier, causing it to slip more easily.
“When that happens,” said Sharp, “the ice is moved faster toward the bottom end of the glacier and that makes it more likely to fail.”
Ice avalanches like the one that occurred at Mount Edith Cavell last August aren’t common, but they’re also not unusual, he said, noting that glaciers in places like the Swiss Alps have ongoing monitoring programs because of previous avalanches that have fallen close to populated centres.
“The speed of a glacier will often accelerate over a period of several weeks before a collapse takes place, so if you’re monitoring the speed on an ongoing basis, you can build that into public safety planning and that certainly does happen in places in the Alps where they know there is a real damage potential for property.”
Pam Clark, visitor experience manager for JNP, said she doesn’t yet know what kind of monitoring system might be put into place at Mount Edith Cavell.
It could be something as simple as having an expert visit the glacier on a semi-regular basis or it could be something as high-tech as a time lapse camera, she said.
Parks will decide on a monitoring system once it receives its risk mitigation option analysis from BCG Engineering. Clark said that study should be complete by the end of the summer.
