Escarpment Slide

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Robert Service Way is now open.

Portions of the Millennium Trail, and Airport Trail are still closed until further notice, due the April 30 escarpment slide, and the public is instructed to avoid the area.

A landslide specialist has been working with data / fieldwork collected by our consulting engineers. The cause of the escarpment slide has been determined to be from saturated soils, as opposed to other work in the area, ice layers, etc. There is clearly a link between saturation and this year’s precipitation levels, which were far above average.

Surveying equipment has been installed into the escarpment, immediately above the slide. This equipment allows us to monitor even the slightest movement. This is critical information in developing a safety plan and a clean-up work plan.

If you witness a slide, please report it to the City’s trouble line at 667-2111.

Learn about making an emergency plan for you and your family here.

Updates

FAQ

Q: How are the sheet piles installed?

A: A local crane and a sheet pile vibratory hammer drives the 12-metre-long piles 9 metres into the ground. It takes approximately 1 hour to install a single sheet pile, and our crews can average 8 to 10 a day.

Q: How big is the wall going to be?

A: The metal wall will stand 3 metres tall, and we’re looking to install a wall that is about 120 metres wide. Since each pile is 1.4 metres wide it’s going to take a lot to finish the project. We will also install a earth berm adjacent to the wall for additional reinforcement.

Q: Are any of the new slides a result of installing the sheet pile wall?

A: Surveying has shown that these latest slides were caused by the high levels of groundwater exiting the escarpment slope.

Q: How do you monitor the escarpment?

A: City crews and geotechnical engineers monitor the slope both in person, and by installing special monitoring equipment. They have also been using a drone to survey hard-to-reach areas.

Q: I live downtown, will someone contact me if I need to leave my house?

A: Only three homes are at risk at the moment, and the residents have all been contacted. Any residents who are required to evacuate will be contacted. The best way to get notified of any emergency, or important City notice, is through Whitehorse Alert. Sign up at whitehorse.ca/emergency.

Q: Are the Black Street Stairs open?

A: The Black Street Stairs remain open at this time. This is an area that is being monitored daily for signs of instability. It is expected that the stairs will remain open unless conditions change.

Q: What about the slides along Wickstrom Road?

A: These slides are fairly minor and normal for this time of the year.

Q: Can't the City just push the mud off to the side?

A: We wish we could, but it’s an active site, and we won’t send our staff and machinery in while the bank still shifting. Many of you have seen the video of the landslide in Seward releasing material and trees around the crew working to clean up their initial landslide. Luckily nobody was hurt, but the video gives you an idea of how fast follow-up slides can occur.

Q: What’s happening with the river?

A: The City is working with the Department of Fisheries and Oceans to determine the best strategy to clean up the debris once it is safe to do so. The goal is to remove as much debris as possible without further disturbance to fish habitat.

Q: Who did the City hire to assess the slide? Who’s working on this right now?

A: Given the complexity and specialized geotechnical knowledge required, the City has retained the firms Tetra-Tech and BGC Engineering. Both have decades of experience in the field of geotechnical engineering.

Q: What are you planning to do to make it safe, after it settles?

A: We’ll be installing sheet piling at the base of the escarpment over the course of the next few weeks. Sheet piles are metal panels that are driven into the ground to provide earth retention and excavation support. The road will remain closed during this time.

Q: Are you working on something more permanent?

A: Yes, we’ll be observing the escapement over the year, and will be planning for a more permanent slide mitigation.

Q: Is the work being done at the bottom of Two Mile Hill related to this slide?

A: No, our crews are repairing a water main at that location. The cliffs above this area much drier than they are nearer to the escarpment slide. A geotechnical engineer assessment had been completed before our Water and Waste Services team started working.

Video taken on May 12 of an active area, just south of initial slide. The sound you hear is groundwater coming down the escarpment.

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Robert Service Way closure map

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Jeckell Street Slide

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