Inside the Report That Changed Bow Glacier Falls Forever

For many hikers, the biggest question after Bow Glacier Falls reopened wasn't whether the trail was accessible again.

It was why.

After last summer's deadly rockslide claimed two lives and injured more than 10 others, what had actually changed?

According to a newly obtained engineering assessment prepared for Parks Canada, the answer isn't that the mountainside has become stable. It's that engineers believe they now have a much clearer understanding of where future rockfalls are most likely to occur and where visitors can safely experience one of Banff National Park's most popular destinations.

The 50-page geohazard assessment, completed by BGC Engineering in March, paints a picture of a mountain landscape that remains active, unpredictable and still capable of producing significant rockfalls. Rather than eliminating the danger, the report recommends reducing visitors' exposure by keeping them out of the areas most likely to be struck if another collapse occurs.

That recommendation ultimately reshaped the hike.

The Mountain Is Still Changing

One of the report's clearest conclusions is also its most sobering.

Engineers say it is "reasonable to expect further rockfalls" from the same cliff that failed in June 2025, as well as other sections of the headwall surrounding the falls.

They point to several reasons why.

The cliff contains overhanging blocks of rock, groundwater continues to seep through cracks in the mountainside and erosion is gradually weakening layers of limestone and shale. Even after the fatal collapse, engineers believe some loosened material likely remained behind and could continue falling as seasonal warming, rainfall and snowmelt affect the rock face.

The report also places the instability within a much longer geological story.

Just over a century ago, the Bow Glacier extended far beyond today's waterfall. As the glacier has steadily retreated, the landscape has entered what geologists call a paraglacial period, an adjustment phase where slopes that were once supported by ice begin responding to entirely new conditions.

Without the glacier, the rock experiences larger temperature swings, repeated freeze-thaw cycles, increasing groundwater flow and the gradual release of pressure that had built up beneath the ice for thousands of years. Together, those processes make rockfalls more likely.

Bigger Rockfalls Often Give Warning Signs

While another collapse the size of last year's tragedy isn't considered imminent, the report says large rockfalls are often preceded by an increase in smaller ones.

Engineers expect relatively frequent rockfalls involving rocks roughly the size of a household appliance or smaller, while collapses involving tens or even hundreds of cubic metres remain possible at any time.

Witnesses to the June 19, 2025 disaster reported hearing several smaller rockfalls in the minutes before the mountainside gave way, observations the engineers describe as consistent with how major rockfall failures typically develop.

Why The Trail Ends Earlier Now

Perhaps the report's most important contribution is explaining why visitors can no longer scramble to the base of the waterfall.

Rather than choosing an arbitrary stopping point, engineers relied on decades of rockfall research to estimate where falling debris is most likely to come to rest.

Using what's known as a rockfall shadow angle, they mapped the expected runout zone beneath the cliffs. The conclusion was straightforward: hikers who remain below that invisible boundary significantly reduce their chances of being struck by falling rock.

The rocky benches closest to the falls, once one of the hike's most popular places for photos, fall squarely inside that hazard zone.

Those same benches were also where many of the injured and deceased were located during last year's rockslide.

Instead of attempting to eliminate a hazard that cannot realistically be removed, the engineers recommend steering visitors away from it.

There Are Still Safe Places To Enjoy The Falls

The assessment doesn't recommend keeping people out of the basin altogether.

In fact, it identifies several locations engineers consider to have only a marginal chance of being struck by rockfall.

Among them are the elevated outwash mound south of the creek, which served as a helicopter landing area during last year's emergency response, and a nearby bedrock ridge overlooking the falls.

Both provide wide views of the waterfall while sitting outside the most likely rockfall runout area.

The report even suggests Parks Canada could eventually improve access to those viewpoints with interpretive signs explaining glacier retreat, the geology of the valley and the natural hazards that continue shaping the landscape.

What About The Lake Above The Falls?

Following last year's tragedy, some wondered whether the lake feeding Bow Glacier Falls could suddenly burst if more of the mountainside collapsed.

The engineers examined that possibility as well.

Their conclusion is largely reassuring.

Unlike the glacial lake that burst at Mount Edith Cavell in Jasper National Park, Iceberg Lake sits behind a natural bedrock dam rather than a loose moraine made of sediment.

That makes a catastrophic outburst flood similar to Jasper's unlikely.

However, the report stops short of dismissing the risk entirely.

Instead, it raises a different possibility. Future rockfalls could eventually alter how water drains from the lake by creating a new outlet through the cliff itself. Engineers say there isn't enough information yet to determine how likely that scenario is, recommending further study rather than immediate concern.

Living With An Active Landscape

Perhaps the report's biggest message is philosophical as much as geological.

The goal was never to make Bow Glacier Falls completely safe.

In a mountain environment, the engineers note, that simply isn't possible.

Instead, they recommend helping visitors make better decisions through clear signage, designated viewpoints and public education, while continuing to monitor the cliff for changes over time.

One particularly novel suggestion is creating a citizen-science photography station where hikers could repeatedly photograph the cliff from the same location, allowing experts to track subtle changes while increasing public awareness of how the landscape continues to evolve.

For visitors returning to Bow Glacier Falls this summer, the biggest change isn't just where the trail ends.

It's understanding why.

The mountain hasn't stopped moving.

Engineers simply believe hikers now have a better chance of experiencing it without standing in its most dangerous path.