Funding approval granted for study of Mt. Currie slides 

Risk to public safety part of investigation

click to enlarge PHOTO COURTESY SQUAMISH-LILLOOET REGIONAL DISTRICT - ROCK AND ROLL Recent rockslides on Mt. Currie have caused officials to undertake a study into slope instability.
  • Photo courtesy Squamish-Lillooet Regional District
  • ROCK AND ROLL Recent rockslides on Mt. Currie have caused officials to undertake a study into slope instability.

The Squamish-Lillooet Regional District (SLRD), Village of Pemberton (VOP) and Líl’wat Nation confirm that Emergency Management BC (EMBC) will fund a Public Safety Risk Assessment regarding the potential rock-fall hazard on Mt.Currie.

In a release Friday, Dec. 2, the SLRD stated that a multi-agency selection and project team, with representatives from the SLRD, VOP, Lil’wat Nation, EMBC and the Ministry of Forests, Lands and Natural Resources Operations (MFLNRO), is the next step to address renewed concern after several rock slides on Mt. Currie. The slides were investigated in an October study by MFLNRO’s Coast Engineering Group, which identified concerns regarding potential instability along the Mt. Currie Ridge and the subsequent potential impacts to Pemberton Valley residents

"We want to understand exactly what's going on up there," said VOP Mayor Mike Richman. "We want to get that study going as soon as possible and then put the information together and put it out to the public."

Both residents and officials have noted recent slides, and geological surveys by air earlier in fall captured photos of rock slides and debris fields.

"We've always known Mt. Currie has the potential to be catastrophic, but what we have now is a little more information about its current condition and an indication that there are enough geological features up there now that we're taking a deeper look, more analysis," said Ryan Wainwright, SLRD emergency program manager.

The slides are nothing new. "They've been going on since the last ice age, if we're going to be accurate," Wainwright said. "The last couple of summers, we've seen more rockfall activity on that mountain, which, because it's so visible from town, has sparked more people to phone us and ask us what the problem is."

Wainwright said the rockfall was not serious and didn't come close to the Green River and was not large enough to cause concern for public safety.

In an email, Gino Fournier, engineer for the MFLNRO report said: "It's unlikely the surface failures we have seen in recent history are linked to permafrost. This needs further investigation... to determine if there is permafrost, as well as other rock mechanics analysis to determine if conditions are present that could lead to larger rock failures." .

An initial rockfall in September was estimated to be between 10,000 and 15,000 cubic metres, but when it was revisited by a geological team 19 days later, the site revealed additional volumes in the range of 20,000 and 30,000 cubic metres — and exposed larger volumes of unsupported bedrock, which could result in more rockfalls.

The report also stated that the potential for failures larger than 100,000 cubic metres are possible due to the highly fractured vertical jointing — but it is unknown if this could result in smaller volumes or one large rock avalanche.

Wainwright said the danger to the people in the valley is "no different than it was two days ago."

"This is an opportunity for us to understand the threat and risks a little bit better, which could contribute to our public-safety planning in the valley," Wainwright said.

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