Hiking Mount Yamnuska? Don't throw rocks from the top, Alberta Parks urges

A rock the size of a tennis ball tossed from the top of Yamnuska will hit the ground travelling more than 200 km/h and carrying more kinetic energy than a bullet fired from a 9-mm handgun.

'It sounds like missiles ripping past you,' climber says of stones tossed dangerously from above

A climber makes his way up Mount Yamnuska, a popular mountain for both climbing and hiking west of Calgary. (Maarten van Haeren)

Twice while climbing the sheer face of Mount Yamnuska, ​rocks have come flying down at Maarten van Haeren from the summit above, narrowly missing him and his party.

"It sounds like missiles ripping past you," said the local climber and guide with the ACMG.

The stones, he believes, did not fall naturally.

The position, trajectory and duration of the rockfall suggest someone up top was tossing them down deliberately but — he hopes — not maliciously.

"I think people are just not aware," he said.

"For a lot of hikers, it's just maybe not on their radar that they're creating a hazard by pushing rocks off the edge or dropping rocks off the edge."

Yamnuska is an imposing mountain, one of the first you'll notice as you approach the Rockies along the Trans-Canada Highway. Less than a hour's drive from Calgary, it's a popular destination for both climbers and hikers.

Mount Yamnuska is one of the closest mountains to Calgary and a popular destination for rock climbers, hikers and scramblers. (Kananaskis Country Public Safety Section/Facebook)

But for inexperienced users following the hiking trail, which veers off to the east before looping back westward to the summit, it may not be immediately obvious that climbers are taking a more direct route — straight up the mountain's 300-metre southern face.

"If you're just coming out and it's your first time in the mountains, you couldn't imagine somebody would take to climbing that face," said Mike Koppang with Kananaskis Public Safety.

While it's inherently dangerous, Koppang said he can understand why someone might want to toss a rock off a massive cliff, believing no one was below.

​"Being as how we are — we're curious people — sometimes we like to throw rocks over the edge to see if you can hear it land," he said.

But consider the physics. A rock the size of a tennis ball tossed from the top of Yamnuska will hit the ground travelling more than 200 km/h and carrying more kinetic energy than a bullet fired from a 9-mm handgun.

Climbers wear helmets to protect against natural rockfall or the occasional stone knocked loose by a climbing partner, but van Haeren said the gear offers only limited protection against brain injuries when dealing with rocks falling from such a height.

A direct hit to any part of the body can do a lot of damage, and even a glancing blow can knock a climber off the wall.

And it's not just climbers who are at risk.

A climber takes a rest and soaks up the views of both prairies and mountains on his way up Mount Yamnuska. (Maarten van Haeren)

In addition to nearly 200 climbing routes on the mountain, there is a hiking trail along the base of the south face that is also exposed to the overhead hazard.

Koppang said Alberta Parks recently updated its website to explicitly remind Yamnuska visitors to not throw rocks from the mountain and is considering installing new signs along the route, as well.

It's a matter of finding the right location for the signs, he added, so that they're visible but don't detract from the views or the alpine environment.

"We don't want to have somebody hike right to the summit of the mountain and the first thing you run into is a sign," he said.

"But I think it's a good idea and it's something we're going to try go get done here."

In the meantime, he said, there's a simple message he hopes visitors to Yamnuska — and all mountains — will take away.

​"Try not to throw rocks over cliffs, because you're not sure who's below you."

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