The rock slide along Highway 97 north of Summerland is not the first time the highway has been closed in that area.
In the late fall of 2008, the highway was closed when a large fissure on the rock slope above the highway was discovered.
This closure lasted 19 days, from Oct. 24 to Nov. 12.
Around 34,000 cubic metres of rock and unstable material was blasted and removed from the site to secure the slope and make it safe for traffic to resume.
The fissure was discovered during a road widening project between Bentley Road in Summerland and Okanagan Lake Park.
This expansion was completed in September, 2010 and created a 35-kilometre stretch of four-lane highway from Penticton to Greata Ranch south of Peachland.
There has also been one other rock slide in this area, in 2014.
Measures were taken to prevent or limit rock fall and to reinstate the slope mesh that was damaged.
Officials with the Ministry of Transportation and Infrastructure say the conditions and geology along this highway are not unique.
“Rock slides of this volume do not occur often,,” a ministry representative said. “The rock slide at this site failed along a natural joint plane deep in the rock slope, and was likely triggered by freeze/thaw conditions.”
The ministry spends $3.5 million each year on rock fall mitigation to reduce potential hazards.
This work begins each spring and involves rock scaling, slope meshing and rock blasting.
“Although rock fall mesh and fencing are utilized as a means of minimizing the impact of rock fall on our highways where possible, they would not eliminate larger events like the one on Highway 97,” a ministry representative said. “Our geotechnical assessment has indicated that in its current condition, the slope will require blasting and scaling to reach more solid rock. This will provide more stability for the slope, and allow ministry staff to remove all loose and unstable rock and eventually reopen the route. The site will also be assessed for further needs as the slope is exposed during the debris excavation process.”
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