A geotechnical expert says the land above the tiny B.C. community of Johnsons Landing is very unstable, and could trigger another devastating slide – but it's nearly impossible to predict if or when it will happen.

Four people were killed in July when debris cascaded down a mountain side burying homes and property in the remote community of Johnson's Landing, 117 kilometres east of Kelowna.

As soon as the ground dried out and stabilized, a geotechnical team surveyed the land above the slide and found a large unstable mass above the debris pile, says provincial geoscientist Peter Jordan.

"We think maybe only half of the potentially unstable material came down in this landslide," Jordan said.

"You can see tension cracks around the perimeter of it in places. So this indicates there is some material that could move."

'The community will live in fear'—Mandy Baths, former Johnsons Landing resident

That means there could be another slide, he said, possibly as large as the last one.

Jordan says it's impossible to predict when and if there will be another landslide, but the hazard is very real. 

"It's like trying to predict where the next thunderstorm is going to arrive. You can give probabilities but you can't predict it with any certainty," he said.

Residents face uncertainty about rebuilding

"We certainly sympathize with them. There is a lot of uncertainty. They have to get on with their lives and we can't give them a firm answer."

The news is a blow to residents who are trying to figure out if they can rebuild their homes, or if they need to move elsewhere.

Johnsons Landing, B.C.

Johnsons Landing, B.C.

Mandy Baths, whose home was crushed in the slide, will not return to Johnsons Landing. Still, she says she feels for those who want to get back to their lives.

"It’s awful news, it’s the worst news. It means the community will live in fear," she said. "If the weather turns bad it’s going to be very scary."

A geotechnical team will meet with homeowners one on one to explain exactly what they found, while local government and the province decide what to do about homes and land remaining at the edge of the original slide path. 

With files from the CBC's Bob Keating