Canadian Consulting Engineer

Construction projects not to blame for Sea-to-Sky Highway rock fall

August 5, 2008
By Canadian Consulting Engineer

The huge rock fall that closed down the Sea-to-Sky highway between Vancouver and Whistler in Vancouver last week wa...

The huge rock fall that closed down the Sea-to-Sky highway between Vancouver and Whistler in Vancouver last week was not on a section of road that had been upgraded. Despite early reports that suggested recent construction nearby might have weakened the rock face, Dave Crebo of the B.C. Ministry of Transportation said the landslide had nothing to do with engineering or construction. “We have to blame Mother Nature for this one,” he told CCE. <br>
On Tuesday, July 29, 16,000 cubic metres of rock fell onto the highway near Porteau Bluffs, south of Squamish. Covering 30 metres of road with blocks up to 10 metres high, the rock fall closed off the main route between Vancouver and the towns of Whistler and Squamish. No-one was injured, although some people had a close call, including one bus whose driver had to speed out from under the tumbling rock.<br>
The next day experts from Thurber Engineering were on site with engineers from the B.C. Ministry of Transportation and Infrastructure to examine the remaining cliff and determine its stability. More sections of fragile rock had to be blasted away to make the road safe again. <br>
The narrow and winding Sea-to-Sky highway carries 14,000 vehicles a day now and will be a critical artery for carrying people to the 2010 Olympic venues in Whistler. The 100-kilometre stretch is undergoing a huge improvement project, involving many consulting engineering companies. Work includes blasting out from the steep mountainside, new bridges and mechanically-stabilized earth (MSE) structures to make the roadway a safer, four-lane highway. The location of the rock fall last week on the side of steep cliff is still a two-lane highway with a CN railway line beside it.<br>
Dry weather followed by heavy rainfall could have caused the steep rock to fracture. As an emergency measure authorities allowed the rock to be pushed off into the ocean below. Some of the debris was trucked off to other construction sites. <br>
The road was reopened on Saturday, August 1, although many people had had to arrange to get back to Vancouver by special $125 airlifts or by boat.<br>


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