About 20 kilometres west of Revelstoke lies a short stretch of BC Highway 1 with a unique geography.
Running in-between Three Valley Lake and the Monashee Mountains, Three Valley Gap is, quite literally, located between a rock and hard place. In fact, next to the Kicking Horse Canyon, this may be the most technically challenging section of the Trans-Canada Highway, in the entire province. We love technical challenges, but not nearly as much as we love keeping the travelling public safe, which is why we are excited to announce the installation of an innovative pilot rock fall fencing system that will help keep people travelling safely in the Three Valley Gap area.
Geography, intense weather and snow avalanches in the area mean standard rock fall fencing would not survive the avalanche activity that takes place along the corridor. So, the new fencing system will reduce the chance of rocks landing on the highway and withstand potential damage caused by snow loading and avalanche activity, without compromising the effectiveness of the remote avalanche control systems that were installed in the area in 2017. The remote avalanche control system also helps the fencing system by keeping the snow avalanches smaller in size – reducing the snow impact on the fencing. We think it’s a pretty great thing.
The fence is approximately 122 metres long and consists of 5-metre high steel posts spaced about 10 metres apart. These posts are supported by a network of steel cables that are anchored 6 metres into bedrock. The slope mesh material consists of two layers of high strength steel rockfall control netting which are hung from the cable supports. This innovative fencing was designed by ministry engineers using materials developed and tested in Europe. If the pilot is successful, this type of system will be considered for other rock fall areas at Three Valley Gap.
British Columbia’s mountainous landscape means our highways pass through some challenging terrain, but our Rockfall Program is dedicated to reducing the rockfall hazard for highway travellers. Do you have a question about this, or anything else the ministry does? Let us know in the comments below.
Did you Know?
In the fall of 2018, a 33-metre long retention wall was also installed in the area to address potential large boulder events.
I have a question for you. can you give me the geo tech that signed off on this job.
Hello Diana – if you would like to speak to someone in our geo-technical group, we ask that you reach out to our regional office in Kamloops. Here’s the contact info:
Southern Interior Regional Office
447 Columbia Street
Kamloops, BC V2C 2T3
Telephone: 250 828-4220
Email: Kamloops.Regional.Transportation@gov.bc.ca
What about all the trees and rocks above the net ? Why not build a road up and over? Just seems like it hasn’t been thought out enough .
Hello Inga – thanks for your comment. By up and over, do you mean up over the mountain at Three Valley Gap?
Unfortunately, the rock in this area is not right for tunnelling and the grade would be too steep, especially in winter to safely drive. Hope this information is helpful.
While the word’s advanced nations build super highways through mountains, Canadians get nets to stop rocks falling on their decrepit goat trails.
Google “China Mountain Highways” and be amazed.
The technology is here, we’re one of the wealthiest countries, yet, somehow, we’re paying hundred of millions of dollars from collective budgets to private shareholders to keep business open instead of just building our own. That sounds more like a hostage situation rather than “economic stimulus”.
Thanks for sharing your opinion with us, Anonymous.
A snow shed, like the ones at the Rogers Pass may be required for avalanche protection for this section of highway.
Thanks for your comment, Pim. Unfortunately, neither tunnels nor sheds are viable due to the unsuitable rock that makes up the Three Valley bluffs. We continue to work on other ways to improve safety at this location.
That section of highway either needs a tunnel (expensive) or a bridge through the lake in order to avoid the avalanche and rock slides.
Thanks for your feedback! Yes – tunnels and bridges are very costly items. This fencing is a trial system which we hope will work well in this tricky spot.
Hope that netting is designed to withstand 30 or 40 years of rockfall and avalanche debris (which often includes rocks and timber). Because it looks like there is no hope of that section of highway EVER being upgraded.
Thanks for your comments Nick – we do appreciate your continued concern.