28 October 2008
Highway 97 update
Posted by Dave Petley
Arthon have posted an update on their website of the situation at Highway 97 in Canada:
“Slight movement in Rock Mass overnight. Road likely closed until Thursday at a minimum. Options being considered for removal of rock”
There is also quite a nice news report with footage here. In the report there is a good description of the use of precursor indicators that can be used to warn of a large-scale failure. They are quite right that movement data, sounds, the opening of cracks and the occurrence of small falls can be used to indicate that a large slip might occur. However, they will need to understand the slope quite well before this option is adopted, and they will need to be particularly cautious when it rains or there is snow melt.
Arthon have published some excellent pictures, including a couple of aerial shots, here. The picture below is the best of them to give an oversight of the problem:
Click on the image for a link to the full size version. Note that a few metres below the main crack there appears to be a smaller tension crack running across the slide, perhaps suggesting that it is starting to break up a little.
It certain looks like a small part of a larger previous slide (extending to the left of the image) that is moving at the minute. Looks like it’s going to be tricky.
I hope they have the good sense to put a video camera on this slide. If it lets go all of a sudden, it would be a shame not to capture it as a movie.
Summerland Waterfront Resort has deeply discounted rates for anyone effected by the road closure.www.summerlandresorthotel.com
I have heard several rumours steming from employees of Arthon that our problems with the highway are just begining. I have heard that the blasting has uncovered a major fault within the rock face that allegedly roots right into the lake. I pray this is not the case, because if it is there will be no easy fix. Please post any comments you have and please report if you have heard any simular stories. If this is indeed true the department of highways is going to have to the cat out of the bag sooner or later.