The District of Peachland is still unsure what caused a small landslide Friday that covered the southbound lane of Highway 97 and brought traffic on the Okanagan artery to a standstill.
The landslide happened at around 1 p.m. PT Friday when nearly a full lane of Renfrew Road above the Highway broke away, sending dirt and trees down onto the highway below.
"We're still looking into the cause of the slide," said Joe Mitchell, the director of operations for the District of Peachland.
"There is active water coming out of the slide area and we're looking to see if this is a natural spring or where this water may originate from."
Drone to help assess slide area
"It's a dangerous area to get into, so we can't get very close to the site. It's still quite unstable near the edges."
Geotechnical engineers plan to bring in a drone later this week to take a closer look at the area.
Last week residents noticed minor cracking in nearby asphalt, Mitchell said the District monitored the situation "but there was nothing significant until Friday morning when it was starting to get a little wider."
"So we brought the geotechnical engineers back in and when they got there they said we should seal off the area and it just continued to crack."
Mitchell said the unstable section remains fenced off and Renfrew Road has been closed to traffic, so there is no risk to the public, though one homeowner still doesn't have vehicle access to their property.
He said the priority now is determining where the water is coming from and why before crews work to repair the road.
"That's probably the only part of the mystery," said Dwyane Tannant, a professor of engineering at UBC Okanagan.
"The water could be coming from some of the services that were under Renfrew Road. The water could be natural water coming from a spring. The water could even originate from things like irrigation systems that weren't properly shut off in the winter."
In motion for days
"Looking at some of the photographs I've seen, it appears there was a pocket of soil that was fairly highly saturated with water and it may have taken days, weeks or months for that water to have accumulated in that specific area."
Tannant drove through the area on Boxing Day and already noticed some slight movement.
"As I was driving down the highway, I noticed at the highway elevation the presence of a small slump so that's at least a week or more prior to it having failed, so there may have been motion occurring for many days leading up to this ultimate collapse of the slope."
Tannant said once crews verify the source of the water, they will then likely excavate the slope and pack in filling with improved drainage.
Highway 97 has been cleared and traffic there has returned to normal.
With files from Daybreak South.
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