South Okanagan - North Beach (Summerland) Rockslide

Initial investigation

After the rockfall event on August 28, Geotechnical engineers discovered tension cracks extending  further upslope beyond the initial rockfall area.

The tension cracks were up to 2 m wide and up to 20 m deep. These findings revealed that the initial rockfall event part a larger event that required mitigation to protect road users and the highway. 

Short term response - reopening Highway 97

To manage the initial emergency, a 22 m high temporary soil and rock berm was constructed along the toe of the slide to resist further slope movement. This temporary berm acts as a buttress for holding back slide movement until long term stabilization measures can be implemented.

During the construction of the berm, a 24/7 slide monitoring program was established. Specialized survey equipment is used to continuously monitor the area for slide movement. If slide movement is detected, the highway can be closed on short notice to protect road users and site workers.

Slide material removal

From October 2023 to June 2024, blasting operations were conducted as part of the effort to unload a portion of the slide mass.  This is to reduce the pressure on the hillside and protect the road from further rockfall. The unloaded material has been moved to off-site storage.

Blasting to remove unstable material above Highway 97 north of Summerland is now complete.

More than 46,500 m³ of material has been removed from the slope since the rockfall in August 2023.

Stabilization

To stabilize the rockslide, steel rock anchors (32mm to 75mm thick and up to approximately 30 m in length) will be installed in the slide zone.

After the rock anchors have been installed, the temporary berm will be removed, and will be replaced by a Mechanically Stabilized Earth (MSE) retaining wall, which will form a buttress to complement the anchors.

Ongoing work

• Highway 97 will continue to support two lanes of traffic
  • The maintenance contractor will carry out regular maintenance to ensure these lanes remain open and safe to the travelling public
• Geotechnical engineers continue to monitor the slide site for changes in ground conditions
• Drivers are reminded that this portion of the road may need to be closed again with limited notice if deemed unsafe
  • The site will be at greater likelihood of closure should heavy rainfall or snowfall occur
• Drivers are asked to use caution, obey speed limits and follow directions of traffic-control personnel
• Temporary stabilization work is nearly complete and the site will safely shut down for the winter months
  • The long-term repair work will begin in spring 2025