UKC

We were up at Twilight Gully on Friday. A fair sized chunk of flake has recently come off in the No Grips area of Twilight Gully Walls. I think it was part of Missing Link.

In reply to harold walmsley:

I was up at the Tower area last night and looking accross, the rockfall seemed to be pretty big. Also to the left of that bit, very near the gully itself in the Bitter Entry area are 2 more areas of very recent rockfall. I had a closer look at these 2 as we walked down (from about 50' away) and my impression is that these are not natural.
Its hard to believe that in such a close area 3 significant rockfalls could all have happened independantly of each other by natural causes in areas which are of good solid compact rock (at least the left hand 2 are, I wasn't close enough to the No Grips bit to see).
Its also hard to imagine that 3 unlucky people could have taken falls causing flakes to pull off when their gear ripped. The rock scars looked more like stuff had been prised or chiselled off, there were no smooth flat surfaces of the sort normally left behind when rocks fall.
The areas are all well above the ground to so if malicious, it must have been done on abseil.
Unfortunately I didn't think to take any photos but if anyone is heading up there soon it might be worth having a little investigation?

In reply to pec:

I live in a land where rock fall, especially during the spring months, is a very regular occurrence but then where I live there's a huge amount of rock. When that rock fall happens on random rock nobody notices, unless it falls into the road. On climbing routes its accepted that it just changes the nature and possibly the grade of the climb.

Only a few weeks ago we were 200 meters up a route up the Croix de Toulouse when we had a massive rock avalanche in a gully to our right. The reason rock regularly falls in gullies is, its a water corridor and water along with frost erodes rock making it unstable. The rock breaks along the crack line the water follows and that doesn't always create a smooth flat surface.

Why would anyone prise and chisel off rock whilst abseiling?

In reply to DaCat:


I don't know, but if you know these crags then you'd know that on some of the most compact and stable areas, the chance of 3 independant rockfalls all happening at near enough the same time in the middle of summer and leaving scars which look totally unnatural (I've seen a lot of rockfall scars) is very unlikely indeed.

In reply to pec:

I think you're right. Looking at the scree slope evidence below twighlight, there are some malicious individuals that have a lot to answer for.

In reply to pec:


The rock fall Harold mentioned relates to a route called missing link and is more than 50 metres away from the 'Bitter Ender' area. Despite it being a fine looking crack climb, it was in fact a VS 4b with no stars. The rock in this area is neither good nor compact. In fact what remains could do with cleaning up as it still appears to be in a dangerous condition and might be a little harder.
I would doubt it came off with a chisel, but if it did then it would hardly have supported a climber as the lump of rock must weigh over a ton and it would have been a very difficult operation. I hope no one was on it when it came detached from the crag. It did not go very far. There is an even larger and older flake that has previously detached itself in the same area. They both look like completely natural rock falls to me.

The scar on the rock right of 'Bitter Entry', despite being in a general area of more compact rock, but judging by the material on the floor, was in fact a quite thin and brittle shield, it looks like it could have been easily pulled off by hand at some time, either to make safe or inadvertently whilst climbing. (Note: if it was compact rock, even a chisel would not have made much of an impact)

The other small scars I think you are referring are small lumps of rock that have come off, I am guilty of inadvertently pulling off a couple of these of myself when I climbed one of the routes. The climb was not that good and I was sort of expecting loose rock, but it was not a malicious act though. (and there are some more holds waiting to drop off)

What does surprise me is that there are not more rock falls in the area than there are, the rock is often brittle and all are in an exposed position, it erodes and weathers quickly being subject to much freeze thaw. Even when the rock looks completely solid it can be partially detached behind the flakes.

More traffic and the routes could clean up nicely, but it is rare to see climbers up there.

In reply to MikeYouCanClimb:

As I said, I didn't get close enough to the "Missing Link" bit to tell what it looked like other than it seemed very large!
It was the 2 bits in the Bitter Entry Area that seemed more suspicious, 3 recent but unconnected rockfalls so close to each other is pretty unusual and the leftmost one looked like about 3 separate bits in itself, presumably this is the one you were on.
I only saw them from the gully whilst descending from the Tower area so not close enough to be sure but worthy of raising on here I thought.
Anyway, thanks for clearing things up.

In reply to pec:




Seems logical to be natural causes to me, all three incidents sharing the same weather. Slate being a laminar rock is particularly prone to exfoliation weathering. Lots of recent rain ingress weakening the bedding plane followed by recent hot spell causing differential heat expansion of the surface layer