Escarpment 2024

News Release via Infrastructure Canada (link)

Whitehorse, Yukon, May 6, 2024 — The Whitehorse Escarpment is experiencing the impacts of climate change and affecting the lives of Yukoners. To mitigate the effects of groundwater seepage causing landslides, the federal government is investing more than $45 million.

Announced by Minister Harjit Sajjan and Mayor Laura Cabott, this work will help protect the land beneath the Erik Nielson Whitehorse International Airport that’s at the top of the escarpment and the main arterial road, Robert Service Way at the base. This road connects the Alaska Highway to the southern entrance of downtown Whitehorse.

Helping to protect the escarpment from future landslides means residents of Whitehorse and surrounding areas will be safe, be able to keep access to essential services, use the Millennium Trail safely, and get to where they need to go without delays from road closures.

To address the reoccurrence of landslides and improve the community’s resilience to the impacts of climate change, Robert Service Way and the Millennium Trail will also be moved further from the base of the Whitehorse Escarpment. Other components of this project include regrading the slope, supporting revegetation, and expanding the debris barrier and implementing anti-erosion measures such as removing rocks and dirt.

Making adaptation investments now will have major economy-wide benefits later. Every dollar of that is invested to adapt and prepare for climate-related landslides along the Whitehorse Escarpment will see more than a doubling in financial benefits.

“The City is excited to be able to move forward with this very significant project. Robert Service Way is a major transportation route for our City – one of just a couple of ways in and out of downtown Whitehorse – serving our residents with a convenient way to get to school, work and many other important places every day. This funding means we can go ahead with our plan to address the landslides that have impacted this road in recent years. I want to thank the Government of Canada for recognizing the importance of this major project and also recognize city staff and contractors for their proactive work to keep the area safe. As we continue to deal with the impacts of climate change, it is important we remain proactive in our efforts.”

Her Worship Laura Cabott, Mayor of Whitehorse

Over the coming days, City crews and contractors will begin constructing a 75-metre, 200-piece lock-block wall along a portion of the Robert Service Way escarpment.

The decision to build the wall behind the concrete barriers already in place follows increased activity along the slope as the spring freshet is underway. The lock-block wall will provide an additional layer of protection against smaller slides.

Robert Service Way and the Millennium Trail will remain open while work is underway but motorists are asked to respect speed limits, signage.

People are asked to use caution in the area at all times as conditions can change rapidly and a road closure may be necessary if conditions become unsafe.

The City’s geotechnical consultants are closely monitoring the escarpment along Robert Service Way following movement over the last 48 hours.

Starting on the evening of April 24, tension cracks began to form as a result of thawing caused by warm weather. On April 25, there was a minor slide of less than 100 m³. Crews have also observed an acceleration of water seepage throughout the slope.

Thanks to the City’s comprehensive monitoring plan, crews were able to respond in real time and have implemented the response plan in order to mitigate the impact of any potential small slides. The existing jersey barriers have been relocated along Robert Service Way and crews are prepared to deploy a lock block wall for smaller slides should conditions deteriorate. In the event that the monitoring indicates a potential for a larger slide further mitigation measures including road and trail closures may be implemented.

Through the use of visual inspections, high-definition imagery, the slope scanner, and the proactive purchase and deployment of jersey barriers and lock blocks, the City is able to keep this important artery open. However, road and trail users should continue to exercise caution in the area and plan accordingly as conditions can change quickly.

The City of Whitehorse continues to monitor the escarpment along Robert Service Way.

The slope scanner and visual inspections confirm the slope is currently stable.

Water seepage is starting to accelerate as temperatures warm, however, there are no signs of instability that would warrant a road closure at this time.

City crews are working towards installing temporary reflective roadway markings along Robert Service Way in an effort to remove the traffic cones currently marking the centre line. This work is anticipated to be completed by the end of the week.

Road and trail users are still asked to maintain caution through the area as conditions may change quickly.

The City of Whitehorse continues to monitor the escarpment along Robert Service Way and conditions remain static.

The slope scanner and visual inspections confirm the slope is currently stable and water is draining from the escarpment as expected during these early stages of the freshet season.

Over the coming days, City of Whitehorse crews will be making minor adjustments to the traffic lane alignment along Robert Service Way and replacing damaged delineators.

Road and trail users are still asked to maintain caution through the area as conditions may change quickly. If you see damaged delineators, or believe delineators are missing, please contact Transportation Maintenance at 633-7669.

The City is proactively shifting Robert Service Way traffic lanes away from the base of the escarpment. Road users can expect to see work ramp up in the area overnight on March 26 and 27. The lane shift will be complete by the morning of March 28.

The road will remain open to vehicle traffic while the work takes place. We ask that you use caution and follow signage in the area. The Millennium Trail remains open for active transportation.

The aim of this work is to reduce the impact of potential landslides by creating extra space between the escarpment and traffic.

Once City crews shift the road, they will begin removing accumulated material from along the base of the escarpment. This will create space for more material in the event that a landslide takes place this spring. This work will not affect the flow of traffic.

As we enter spring, the City is preparing for freshet on the escarpment along Robert Service Way.

The City is taking a proactive approach to escarpment monitoring and maintenance, building on the work done in 2022 and 2023 to protect Robert Service Way and trails in the area. The escarpment will be monitored through a variety of methods including:

• radar-based slope scanning;
• visual inspections;
• groundwater level monitors;
• targeted survey monitoring of critical slope areas; and
• drone surveys.

If movement is detected along the escarpment, the City is acquiring 400 concrete lock blocks to build a retaining wall at the problem area. This will help mitigate against small volume slides along Robert Service Way.

Traffic lanes will also be proactively shifted away from the base of the escarpment, likely at the beginning of April, unless conditions change significantly.

The City is also planning for a long-term solution along the escarpment. Pending funding, the City plans to realign the north end of Robert Service Way by moving it away from the base of the escarpment and re-grading the slope in 2026. In partnership with the Government of Yukon, the City applied for the federal government's Disaster Mitigation and Adaptation Fund to support this long-term plan to lessen the impacts of potential future landslides.

Slope instability along the escarpment and Robert Service Way are now a regular occurrence and spring closures to the road and trails in the area should be expected annually until a permanent solution can be implemented.