South Apron reopen July 5th

[squamish climber]

Stopped by the Apron parking lot this morning on the way to Rock On. They had the lot closed off. Spoke to ranger Katy there, she said the scaling crew were just wrapping up and the climbs should be open by 10 am. She said an engineer was up there and determined the source of the rockfall was just above where the photo was taken.
If anybody has more info please update.
Safe climbing everyone
(posted via iPhone)

[asc]

Just got down from apron. Cleared the offending block. No bolts were affected but lots of dust and small debris on routes below the obvious rock scar. Apron open.

The sickle still has a hollow block that is only partially attached, but it is no worse than blocks above. I think some of the old guide books suggest a belay right where the new scar is. I wouldn't recommend this because of the expanding block and the damaged tree. No issues climbing through with protection above and below the scar. Be ready to brush some footholds.

We cleaned the large stuff but there is still some new debris on the start ledge of diedre. We did not have a close look at the rambles/lower apron area so extra caution this morning.

[squamish climber]

Good speedy work by you and the team. Thanks for getting it done and before the weekend too. It would be great if you have any pictures to post later or email me
Thanks again.

[tsouth]

Great news. In time for the american invasion.

[squamish climber]

I received a photo that Frank Baumann the geologic engineer (and long-time Squamish Climber) took of the rock fall. He and a crew of scalers worked hard at getting the Apron safe for re-opening by Friday morning.


Here is the text that accompanied the photo:
Here is the picture I took this morning (July 5) of the rockfall area on the Apron- you can clearly see the initiation point and then how the rock cascaded down the slope.

Any geologists out there want to chime in on the likely cause of this rockfall and potential for more from this zone?

I was reminded by someone that last year around this time after a very heavy rainfall there was a significant rock fall on the backside Chief trail. Anybody remember that?
For a reminder here is a picture of that :

[squamish climber]

Received an update from Frank this afternoon regarding the rockfall:

The Sickle failure was quite puzzling- the rock seemed to have shattered in that spot, so I'm not sure what the underlying cause was. It's possible that thermal expansion played a role- but rock is actually a very poor conductor of heat, so it is doubtful that it was responsible. Back in the mid-1960's there was a much larger slab that broke out at about the same place- I was there at the time and can't remember if it was at the exact same spot or on the next slab up (just below the crux move). In any case, it is an area of some perplexing stress.

Anyway, I just hope that everyone realizes that B.C. Parks made an exception in this case to deal with the rockfall- mainly because it threatened the most popular starting point for several of the Apron routes, and also the B.C. Hydro transmission lines and, possibly, Highway 99 (doubtful). But anyone climbing on the Apron must realize that there is a certain amount of inherent risk up there that can't be avoided, and would be entirely impractical to manage.

[staven]

Here is the picture I took this morning (July 5) of the rockfall area on the Apron- you can clearly see the initiation point and then how the rock cascaded down the slope.

Is the "initiation point" that big white gash at the top of the Sickle pitch? Aren't those fresh scars above that white gash as well, basically in line all the way down to the bottom? I thought the block was sitting above the OTR arch? It looks more like the rock fall came out from 2 pitches up or so - If so, did the scalers assess the upper area, or just trundle the block? It would be strange for Frank and BC Parks to have declared the climbs open if there is an unassessed hazard farther up, so I must be missing something.

[asc]

We rapped in from Broadway (3x) and checked everything from Diedre to Banana Peel for scars, tree damage or anywhere that the rocks may have come from. Frank took hundreds of photos from ground level and with his little drone. It is strange but tension at the top of the OTR arch literally made the blocks just pop out and it will likely happen again.

The other white spots are just that....white spots. They are under roofs or areas where moss has been moved. There is, however, tonnes of loose rock and wobbly flakes all over the upper parts of those route that could come down with torrential rains or if someone was careless pulling a rope.

[geoffgeorges]

I am no expert, but have climbed OTR regularly for 12 years and have always noticed that area being loose and wet underneath the very spot blown out. In another picture there is a block perched on the back of the small tree, which makes me think that something came down from above, maybe the tree ledge above? Or was that flake on the tree just from right behind it?
I was on it again 2 weeks back and above the scar the little ledges are all loose till you get up to the slab with the one bolt move.