It could be weeks, even months before traffic returns to normal in the British Columbia's Okanagan.

Highway 97 remains closed to traffic seven kilometres north of Summerland after a huge crack appeared above the site of a highway widening project.

An unstable rock face above Highway 97 has been shifting, and there are fears it could come crashing down on the road below.

As a result traffic is being detoured via Highways 97C, 5A, 3, and 3A. This is the recommended route for commercial trucks in excess of 27,000 kilograms and buses. Also, Okanagan Falls Forest Service Road to HWY 33 is now available.

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Since Monday night, the mass of rock moved another 15 millimetres. An estimated 200,000 cubic metres of material have broken away from the hillside north of Summerland, creating a crack over a metre wide.

Even the top geotechnical engineers in the province are having a hard time guessing how long it's going to take to make this section of highway safe for travel once again.

On Tuesday, the Highways Ministry's top geo-technical engineer Mike Oliver explained how crews plan to strengthen the toe of the slope with a large berm, while blasting from the top.

"To increase the weight at the toe of the unstable mass such that the toe should act as a supporting mass for the unstable rock,'' Oliver said.

As early as Wednesday, blasting could begin from the top of the slide.

Most of the scattering of properties below the slope failure are not in the pathway of any potential slide. But the impact of the road closure has hit them hard.

Most have connections to Penticton, connections that are now cut off.

Geotechnical engineers say it could be a number of months before the slope can be made stable enough for traffic to pass.

Ultimately it's believed most of the material down slope from the fissure will have to be removed.

And if it can be taken down safely, crews are still left with a massive job with about 20 truckloads of rock to take away.

Meanwhile, police are warning travellers about using the detours, saying the alternate route, which includes a logging road, can get snow this time of year and people should be prepared for winter driving conditions.

They also say cell phone coverage in the area is sporatic at best and if anyone has trouble they may be forced to remain with their vehicle until help arrives.

With a report by CTV British Columbia's Kent Molgat and Lisa Rossington.

With a report by CTV British Columbia's Kent Molgat and Lisa Rossington.