Size and complexity of Highway 97 rockslide make predicting reopening impossible, ministry says

The rockslide that closed Highway 97 north of Summerland this week is a repeat of a slide that occurred in 2008, and is significantly larger than the amount of debris that ended up on the roadway, according to the provincial Ministry of Transportation and Infrastructure.

In an interview with CTV News on Friday, Steve Sirett, the ministry's executive director for the Southern Interior, refused to speculate on when the road could be safe to reopen.

"We are doing a lot of work to understand when we might get to that point," he said, nothing that crews are still collecting data to try to determine the risk of further slides and what mitigation steps are necessary to prevent them.

"Unfortunately, because of the size of the slide and complexity, that is going to take some time," Sirett said. "So, at this point, I don't have an expected time of when we might get it open."

The ministry said Tuesday that the rockslide dumped about 3,000 cubic metres of material onto the roadway between Bridgeman and North Beach roads, about a kilometre north of Summerland.

That's only a "small, small portion of the slide," according to Sirett, who said officials are concerned that more rocks could fall.

"There is some pretty significant tension cracking above (the slide), you know, two to three metres wide, at least five metres deep from what we can tell now," he said. "So, the total estimated slide volume is, you know, a couple hundred thousand cubic metres of material, which is a significant amount."

The highway has been closed since roughly 2 p.m. Monday, and the Regional District of Okanagan Similkameen placed four properties on evacuation alert because of the slide on Wednesday.

The province announced Friday afternoon that one lane of the highway would be cleared for use by emergency vehicles only, which will take place "under specific site safety protocols." It did not say when emergency vehicle access would begin.

Sirett confirmed that the area was the site of a previous landslide that caused a "lengthy" closure of the highway 15 years ago.

"This is a slide that occurred in 2008," he said. "We did a lot of mitigation work to try and stabilize it at that time. And you know, it did remain stable for about 15 years. So that's a pretty good stretch for that to remain stable."

The fact that the current slide is in the same location means there's historical information crews can refer to as they work to get the road reopened this time around, Sirett said.

In the meantime, the ministry has started daily maintenance on two forest service roads that serve as detours between Summerland and Peachland and between Penticton and Kelowna.

Those routes still add a significant amount of time to the trip, and Sirett said crews are working through the long weekend to gather more data about the slide and increase the likelihood of the highway reopening.

"Every day of data gets us that much closer to understanding how we're going to stabilize it and – if we can open it – to open it safely," he said.