Work crews at the site of a massive rockslide blocking the Sea to Sky Highway near Vancouver made the first major blast to remove unstable debris on Thursday.

The initial detonation has removed an estimated 2,000 tonnes of unstable rock from the front of the cliff face.

Provincial engineering and rock scalers made the decision to blast the front of the face after spending most of Wednesday assessing the stability of the cliff.

Now that the initial blasting is completed, crews can start drilling and blasting the massive boulders on the vital artery.

But it will be at least four days before the highway is reopened following the slide on Highway 99 -- the only direct route between Vancouver and Whistler, the intended venue for many of the 2010 Olympic events.

The slide occurred at just before midnight on Tuesday when the face of a large cliff broke loose, sending at least 16,000 cubic metres of debris onto the section of road near Porteau Cove.

"We've mobilized a fair amount of equipment and we'll do whatever it takes to get the road open as fast as we can," Mike Oliver, B.C.'s chief geotechnical engineer, told reporters near the site of the slide.

Rock bolts were installed in the area a few years ago to hold the rocks in place, said Oliver, who added there has be no sign of instability there "for a considerable period of time."

"It's a geologically active province and this is in a steep mountainous terrain, so there's no guarantee that we won't get any," he said.

It normally takes motorists a few hours to drive the highway from Vancouver to Whistler, compared with up to eight hours that motorists now face in taking the alternate route through Duffy Lake and down through the lower Interior.

Meanwhile, BC Ferries was considering an interim ferry service to help stranded travellers, but now says the available dock in Squamish is not workable.

Several companies have set up private water taxi service between Squamish and Horseshoe Bay, and helicopters are offering chartered flights, but both are costly and often confusing options.

In the run-up to the long weekend, Whistler Mayor Ken Melamed says the closure will be a big headache for the city of Whistler. The resort village normally receives thousands of tourists over the August long weekend.

"It's one of those things that happens that comes out of the blue and we'll try to deal with it as fast as we can," said B.C. Premier Gordon Campbell, speaking to reporters on Wednesday.

Peter Skeel, a shuttle bus driver who narrowly avoided being caught in the slide, told Canada AM he had no warning that it was coming.

"Suddenly there was this raucous, incredibly loud noise. It was unbelievable the noise that was being produced. We really had no idea where it was coming from originally until it settled down afterwards and we realized there had been a rock slide," Skeel said.

The bus suffered serious damage with three of the vehicle's large windows smashed by boulders.

"We actually did not hear those windows break, that's how loud the noise was, until we pulled over and were able to examine the vehicle afterwards," Skeel said.

Louis Araujo, a passenger who was on the shuttle returning to his home in Whistler, credited Skeel with saving his life by driving through the rock fall.

"It was as close as it could be without dying, basically," Araujo told Canada AM.

"It was really a matter of seconds. A few seconds later and the rocks would have been piled on top of us."

Olympic-sized worries

Much of the Sea to Sky Highway is being improved to meet the needs of the 2010 Games. In total, $775 million in upgrades are currently underway, including widening to add extra lanes to increase volume.

After the slide, there were worries about how a another one could affect the 2010 Games.

But on Thursday, a spokeswoman for the Vancouver 2010 Winter Games committee (VANOC) downplayed the impact a rock slide would have.

"We have to have contingency plans in place for something like this --and also for a number of other 'what ifs' that might happen,'' Cathy Priestner-Allinger said. "We're also in the process of working on those."

Officials had planned to do some shoring work on the very rock face where the slide happened, but ironically there was no construction taking place at the time, said CTV British Columbia's Stephen Smart.

"It seems like this really is Mother Nature saying 'I'm the boss here and you're trying to build in a tricky area and there are risks to it,'" Smart said.

Oldrich Hungr, a professor of geological engineering at the University of British Columbia, said the highway -- which was considered the Achilles heel in Vancouver's bid for the Olympics -- cuts through a fragile region.

"The rock is reasonably good quality but it rises very steeply from the sea and it is cut by a special type of joint -- cracks which happen to incline out of the slope. So blocks can slide over them and that has been a problem ever since the construction of the highway," Hungr told Canada AM.

However, using data he collected several years ago for a rock-slide risk assessment, Hungr said the risk is minimal that a rock slide will happen during the Olympics.

"It has to be compared with other risks," he said. "If you ran the Olympics 500 times, one of those times the highway would be cut with a rock fall."

Still, Arauja said any interruption to traffic on the road is a blow to those who live in Whistler.

"I'm concerned because it's really the lifeline, it really affects our lives and our businesses," he said.