If you are travelling up and down the Sea to Sky Highway, you likely noticed the crews along the side of the road, particularly near Porteau Cove Provincial Park.
The crews, contracted by the provincial Ministry of Transportation and Infrastructure (MOTI), are often rock scaling.
Rock Scaling, by the Ministry’s definition, means removing loose rock from the slope by rock scalers who are suspended on ropes using pry bars.
This prevents the rock from falling on the road below.
Before work begins, a geotechnical engineer will assess the site and identify spots of the slope that require stabilization; these could include rock overhangs that may need trimming and areas that require scaling, according to the Ministry.
“Slope stabilization work, including rock scaling, is an important part of the ministry’s contracted maintenance along the Sea to Sky Highway, to keep drivers safe and the highway open,” a Ministry spokesperson told The Squamish Chief.
According to a detailed description of the work on TranBC, a MOTI website, the rock scalers wedge a pry bar — like a crowbar, a hand tool used to pull two objects apart — into open spaces on the slope to check for loose rock and remove it.
“On larger rocks, they may place rubber airbags between rock joints and inflate the bags with compressed air to dislodge the unstable rocks. Tools used for this work may also include jacks and hydraulic splitters. The work may need to be supplemented by controlled blasting, especially when trimming of a larger area of rock or outcrop is required,” reads the website.
The $800-million Sea to Sky Highway Improvement Project — which upgraded 95 kilometres of the highway between Vancouver and Whistler, was completed in 2009 in advance of the 2010 Olympic Games — included improved rock fall and debris catchment areas along the corridor, the MOTI spokesperson said.
The maintenance contract for Highway 99 requires that an annual assessment be completed of all known areas of instability that could pose a risk to road users and to the highway.
According to the Ministry, this includes monitoring adjacent side roads for rockfall hazards.
The preventative rock scaling work took place near Porteau Cove over the weekend.
Work is done in two phases: rock scaling and bolting.
Why not use a machine?
The height and detailed work of scalers requires humans on the rockface rather than using, for example, excavators.
“Care must be taken not to over-excavate or undermine sections of the slope. Too much excavation could weaken the slope and result in more rock coming down over time,” reads the TranBC post about scaling.
Drivers can check DriveBC for updates on scaling occurring along the Sea to Sky.
Watch rock scaling in action in Sherman Pass
*Please note that The Squamish Chief asked the Ministry to connect us with a local rock scaler, but MOTI said no one was available to be interviewed.
**Please note that this story has been corrected to note that the Sea to Sky upgrades cost $800-million, according to the 2012 BC auditor general report, not $600 as first posted.
