It could take five days to reopen the Sea to Sky Highway between Whistler and Vancouver, which is blocked by a rock slide, B.C. Transportation Minister Kevin Falcon said on Wednesday.

Rock scalers, who will remove loose rock from the cliff above the highway, and engineers were working together to assess the stability of the cliff face Wednesday, said Falcon, who had taken a helicopter tour of the site on Highway 99 between Lions Bay and Furry Creek.

"The main challenge is that there's still some rock slab up there that we have to take a look at to determine if there's a risk of it of coming down," Falcon said.

The rockfall late Tuesday night sent an estimated 16,000 cubic metres of rock down onto the highway, the only direct route between Whistler and Vancouver. A bus carrying one passenger made it through the area just as the slide was coming down. There were no reports of any injuries.

A rock slide blocks the Sea to Sky Highway near Porteau Cove, B.C., Wednesday, after a cliff face collapsed onto the highway late Tuesday night. (Jonathan Hayward/Canadian Press)

Falcon said geotechnical engineers are expected to finish their preliminary assessment in the next 24 hours but the 75-metre section of the highway will remain closed to traffic for at least five days.

"We have equipment at both ends of the site to start to clear some of that rock out but, obviously, we can't put those workers too far into the centre of the collapse because it would put them potentially at risk," he said.

"We can't just push all the rock into the water, which will be the easiest thing to do to get this highway cleared out.

"But the DFO federally doesn't allow that so we're going to have to move all of the rock to staging points at either end of the highway and that will take a little more time," Falcon said.

Interim transportation by ferry unlikely

Falcon said he spoke to BC Ferries about the possibility of having a ferry to move people stranded by the slide from a dock in Porteau Cove to a dock in Darrell Bay in Squamish.

"But it's not looking good [because] it's a dock that hasn't been used for many years," he said. "Ferry engineers are taking a look at it to see whether it makes any sense."

The cause of the rock slide has not yet been determined but geotechnical engineers believe a long period of hot, dry weather followed by rain in the last two days triggered the natural disaster, Falcon said.

The Sea to Sky Highway has been undergoing extensive widening and upgrading at a cost of $600 million in preparation for the 2010 Winter Olympics in Vancouver and Whistler, but Falcon said there was no construction work near the immediate area of the slide.

Overall transportation plan in the works

B.C. Premier Gordon Campbell said the massive rock slide is no reason to build another route from Vancouver to Whistler and Pemberton.

The rock slide happened just north of Porteau Cove on Highway 99. (CBC)

"It's an accident and it's one of those things that comes out of the blue and we'll have to deal with it as quickly as we can," Campbell said.

But the premier said measures will be taken to make sure the route is safe during the Games.

"Prior to the Olympics, one of the things that is scheduled is to go through all of that area and just check it and make sure it's OK," said Campbell.

The Vancouver Organizing Committee of the 2010 Olympic Games said in a statement on Wednesday that it has been working with the Ministry of Transportation on "overall transportation plans for the 2010 Winter Games, including important planning for the Sea to Sky corridor.

"To mitigate any short term transportation challenges between Vancouver and Whistler, athletes, officials and the majority of personnel required to stage an Olympic or Paralympic event in Whistler will be housed in the Whistler area so events will proceed on schedule," Irene Kerr, vice-president of services and transportation, said in the statement.

Communities deal with blocked highway

Whistler Mayor Ken Melamed said the closure of the highway will be a major headache for the resort village.

Melamed said the Sea to Sky Highway is critical to the economies of all the communities along it and he was hopeful ferry service might be arranged around the slide area.

Meanwhile, the acting mayor of Squamish said residents are accustomed to Sea to Sky Highway closures.

Greg Gardner said the closure will affect residents who commute to Vancouver for work as well as the movement of goods and services.

The only other vehicle route is a day-long detour through Pemberton, Lillooet, and Lytton to Vancouver. There are planes and helicopters at the Squamish airport, he added.

"The good news we have to date is we have no evidence of any casualties," said Gardner.