SQUAMISH, B.C. — The Sea-to-Sky Highway may not re-open until tomorrow, after a rock slide near Porteau Cove Tuesday night blocked traffic in both directions.

“Today is looking unlikely,” Ministry of Transportation spokesman Dave Crebo told The Vancouver Sun after crews began assessing the damage yesterday morning.

The slide, which occurred at 11 p.m. Tuesday, resulted in officials closing traffic from Lions Bay to Furry Creek Bridge (south of Squamish). Crebo said geotechnical engineers are now on site trying to assess the damage and determine the safest and fastest way to clear the debris. RCMP and West Van Police turn motorists around at Horseshoe Bay after an overnight rock slide on Hwy 99.

“They’re trying to gauge the magnitude of the slide and the stability of it,” said Crebo. “Until we hear back from them, we can’t say with any certainty when the road will be open.”

However, Crebo said initial reports from the area indicate it’s going to be a tough job. “Some of the debris is still hanging precariously (over the road),” said Crebo.

Earlier reports suggested some of the boulders in the slide area are the size of cars. Crebo said that some of the larger boulders may need to be blasted before crews with heavy equipment can move the rest of the debris off the roadway. “Obviously we want to get that highway open as quickly as possible,” he said.

Crebo said the area where the slide occurred is not part of the Sea-to-Sky Highway Improvement Project, so it has not been worked on recently by construction crews. The area around the slide – like all sections of the highway – is subject to regular slide mitigation by the ministry, such as pre-emptive blasting, rock bolting and rock scaling, in which crews knock off loose pieces of rock near the highway. Crebo said he didn’t know the last time the area affected by the slide had received slide-mitigation work.

The slide has inconvenienced many people who use the highway to get to and from work. But that’s nothing compared to what might happen if such a slide were to occur during the 2010 Winter Olympics, blocking access to competition venues and embarrassing B.C. on the world stage. Crebo said the ministry plans to beef up its slide mitigation activities in the months leading up to the games.

“The ministry and the province will be doing everything they possibly can to lessen that risk. And so the summer of 2009, there’s going to be quite an effort going on there,” he said. “Is it a 100% guarantee? No. That’s the nature of the terrain we live in.”

CN Rail has a track adjacent to the highway, and it was also effected by the rock slide. However, the Vancouver CN communications officer would not elaborate about the extent of the damage. Kelli Svendsen did say that the railway company is working with B.C.’s Ministry of Transportation and Highways, in “assessing the situation,” but could not offer a timeline, about repair to the track, or a return-to-service.

“We don’t have an estimated time, when it will be open,” she said.