Beinn Bhàn hazardous holes

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 DaveHK 21 Feb 2023

I've just noticed the following note in the 2011 SMC Journal:

'Two large holes on the plateau near the top of Gully of the Gods are now a hazard in winter. The larger hole is at NG 80220 45480, 863m, 10m from the cliff edge.'

I've been up that way a few times and never noticed such holes. Has anyone else? Presumably the hazard would be falling in them in which case they must be pretty deep!

 Lankyman 21 Feb 2023
In reply to DaveHK:

If close to the edge they sound like landslip features? I've seen deep rock crevasses in schist in the Arrochar Alps and also above Glen Clova at Loch Brandy. There'd been a huge recent landslide above the loch so they look prone to movement. Covered in snow they'd be a hazard.

OP DaveHK 21 Feb 2023
In reply to Lankyman:

If they're getting bigger as the comment suggests that could be a real worry as they're not far from the cliff edge which might suggest big movements.

 Sean Kelly 21 Feb 2023
In reply to DaveHK:

Never seen any, but then I wasn't looking for any.

 iainJ 21 Feb 2023
In reply to DaveHK:

These are very visible in aerial imagery - there's 4 clearly visible on google earth (link below) and I think a couple more on higher resolution photos I looked at. Sadly, having had a quick glance at the regular Sentinel images it doesn't look like they are high enough resolution to see the features, if they're changing with time or when they first developed.  https://www.google.com/maps/place/57%C2%B026'47.1%22N+5%C2%B039'52.6%22W/@5...

Post edited at 15:25
 andyinglis 22 Feb 2023
In reply to DaveHK:

Never thought to mention this to you as presumed you knew, apologies! Yes when you walk off right (north) from the top of the godfather buttress area towards the descent slope there is at least 1 hole / rock crevasse that you need to watch out for. Can’t recall exactly but its not far off where Great Overhanging would top out I think….

Andy

 elsewhere 22 Feb 2023
In reply to iainJ and CurlyStevo:

Quite strange, it's like a gully mostly bridged but by earth rather than by snow. An ancient gully filled by muck that is now being emptied by erosion at an open end to the east??????

Is there a geographer or geologist in the house?

In reply to elsewhere:

I'd presume it's Gully of the Gods cutting much further back into the hill than might be immediately obvious. Any brave cavers out there? 

 Lankyman 23 Feb 2023
In reply to elsewhere:

Apart from sea caves I've not come across cave development in Torridonian sandstone such as you'd get in limestone. Given the location of the holes close to a cliff edge and their linear position I suspect they are a fracture feature. Given time the whole lot will slump over into the corrie. It's a long way to go with some caving gear. I'm not a geologist but used to cave a lot including in Scotland.

 Mark Bull 23 Feb 2023
In reply to elsewhere:

There are dykes cutting through the sandstone thereabouts - there's one visible on the north side of Coire an Fhamair (towards the right hand side of this shot https://www.flickr.com/photos/paulsammonds/5078773580 ). I wonder if the holes could be a similar feature which is eroding out, rather than a widening fracture. 

> It's a long way to go with some caving gear. 

Could be record-breaker though: highest cave entrance in the country? 

 Lankyman 23 Feb 2023
In reply to Mark Bull:

> > It's a long way to go with some caving gear. 

> Could be record-breaker though: highest cave entrance in the country? 

I suppose it depends on how you define a cave? I'm not aware of any particularly high altitude limestones in Scotland where you'd get 'proper' caves (formed by water action) rather than howfs in boulders, rock shelters or slip features. As far as I know, the highest proper caves in Britain are up on Knock Fell in the North Pennines at about 760m asl. I've seen a few 'Prince Charlie's Caves' on the map (he was definitely an early speleologist) but they are more like shelters or boulder howfs.

 John Lyall 23 Feb 2023
In reply to DaveHK:

They look like a fault line revealing a massif landslip in it's early stage. I wonder how long it will take for that wonderful cliff to fall down? If you haven't climbed there, get on it before it vanishes, or some great new lines appear. 

 Cog 23 Feb 2023
In reply to DaveHK:

I sent Noel a link to the photos, his reply is below.

'It looks like the summit is capped by moraine, and over time rain has started to wash it into the underlying rifts in the bedrock.'

OP DaveHK 23 Feb 2023
In reply to Cog:

> I sent Noel a link to the photos, his reply is below.

> 'It looks like the summit is capped by moraine, and over time rain has started to wash it into the underlying rifts in the bedrock.'

Sounds plausible.

 andrew ogilvie 24 Feb 2023

m In reply to Mark Bull:

Not much chance of it being the highest cave entrance in the country I'm afraid the Grampian Speleology Group have recorded one high on the Strath Ossian/ Loch Pattack Munros with an altitude of 895m. There are other caves in Applecross though so a visit by cavers might not be as unlikely as you might think

https://registry.gsg.org.uk/sr/sitedetails.php?id=3724

 andrew ogilvie 24 Feb 2023
In reply to Lankyman:

There are some caves noted in the corrie on Beinn Dubhcraig and at least one really quite high on the mountain probably around 800m altitude about due north of the summit which I have grovelled into,  however a "cavern measureless to man" it is not.
On reflection, these many years later, this was probably not one of those recorded by the GSG explorations of Jim Salvona but I can't find my "caves of the Southern Highlands" book to be sure.

There are caves in Coire Mulrooney above Glen Creran but my explorations of this area never took me so far up the hill as there are plenty of caves lower down in the Coire Shielach area if you like that sort of thing...these Mulrooney caves may not really be much higher than the upper Schiehallion caves but you'd have to start from sea level to get to them...which hardly seems fair.


 

 Lankyman 25 Feb 2023
In reply to andrew ogilvie:

> m

> Not much chance of it being the highest cave entrance in the country I'm afraid the Grampian Speleology Group have recorded one high on the Strath Ossian/ Loch Pattack Munros with an altitude of 895m. There are other caves in Applecross though so a visit by cavers might not be as unlikely as you might thinkhttps://registry.gsg.org.uk/sr/sitedetails.php?id=3724

That's really interesting. Thirty years ago we passed within a few hundred metres of that cave during our foray to bag the Alder and Aonach Beag Munros. I'd no idea there was any limestone (let alone caves) in that area.

 Lankyman 25 Feb 2023
In reply to andrew ogilvie:

https://registry.gsg.org.uk/sr/sitedetails.php?id=3724

I've just been using this very useful link to check out some limestone I came across in Ardnamurchan ten years ago on Ben Hiant.  There doesn't seem to be anything noted so could be a new caving area waiting to be investigated?

https://www.geograph.org.uk/photo/3377048

Check out the features north of where I took that photo as well - looks like streams sinking on the map and the name Lochan Poll an Dubhaidh suggests a cave of some sort. You can click on the Geograph map and get a zoom-able version.

Post edited at 09:18
OP DaveHK 25 Feb 2023
In reply to DaveHK:

Holewatch update...

At the holes right now and they don't look like they lead to much.


OP DaveHK 25 Feb 2023
In reply to DaveHK:

Lovely day though.


 Lankyman 25 Feb 2023
In reply to DaveHK:

> Holewatch update...

> At the holes right now and they don't look like they lead to much.

Get digging - some of the biggest caves in Britain have been discovered this way!

 kwoods 25 Feb 2023
In reply to DaveHK:

> Holewatch update...

> At the holes right now and they don't look like they lead to much.

I'm just wondering what's through that little black crevasse!

OP DaveHK 25 Feb 2023
In reply to kwoods:

> I'm just wondering what's through that little black crevasse!

I didn't get a phone shot to post but if you're look at the top of Gully of the God's there's a chimney crack that runs through into where the holes are. So it's obviously quite a big feature.

 iainJ 25 Feb 2023
In reply to DaveHK:

Have you got a slightly more zoomed out photo? It seems like the crag side of the holes, opposed to the summit side, is slightly lower.

Combined with what you say about the chimney crack extending into the cliff, this has the hallmarks of being a tension crack at the head of a landslide.

 elsewhere 25 Feb 2023
In reply to DaveHK:

Live reporting from UKC's correspondent on the spot!

OP DaveHK 25 Feb 2023
In reply to elsewhere:

> Live reporting from UKC's correspondent on the spot!

Capped off by fish and chips in the Applecross Inn!

OP DaveHK 25 Feb 2023
In reply to iainJ:

> Have you got a slightly more zoomed out photo? It seems like the crag side of the holes, opposed to the summit side, is slightly lower.

> Combined with what you say about the chimney crack extending into the cliff, this has the hallmarks of being a tension crack at the head of a landslide.

The crag side of the holes is higher and it dips away behind them. I've got a shot of the crack on my camera so I'll post it when I'm home if you're interested. Obviously it's hard to say but it doesn't look like anything is going to collapse in the near future. If there was a failure at that point it would be gigantic as its probably about 50m from the edge. The fault runs roughly parallel with the cliff edge and you can see from the grass that it extends past the holes.

1=Great Overhanging Gully

2= Gully of the Gods the crack is in the gully wall roughly where the 2 is.


 HardenClimber 25 Feb 2023
In reply to Lankyman:

Limestone isn't essential.

Occasionally caves form in sandstone as a rift opening up through subsidence, sometimes keeping a roof. Very occasionally the are a reasonable length eg Pan Holes http://cavemaps.org/surveys/crg/full/CRG%20T1-4%20Pan%20Hole%20-%20Bingley....

There are a few others scattered around. Several sandstone mountains have quite deep slots in them -  Beinn an Eoin springs to mind.

 Lankyman 25 Feb 2023
In reply to HardenClimber:

> Limestone isn't essential.

Yes, you're right. I never said it was essential. It depends on how you define a 'real' cave. Most water formed caves are in limestone. As far as I know British sandstone doesn't form caves in this way although there are significant sandstone caves in Venezuela because of the climate there.

> Occasionally caves form in sandstone as a rift opening up through subsidence, sometimes keeping a roof. Very occasionally the are a reasonable length eg Pan Holes http://cavemaps.org/surveys/crg/full/CRG%20T1-4%20Pan%20Hole%20-%20Bingley....

I've squirmed through a few things like this. There are also lots of slip caves ('windy pits') in the North York Moors limestone.

> There are a few others scattered around. Several sandstone mountains have quite deep slots in them -  Beinn an Eoin springs to mind.

I've not seen them on sandstone myself but I have seen plenty of them on schist mountains like the Arrochar Alps.

Just noticed you're Craven PC. We've possibly crossed paths down a cave/in a Dales pub/Bernie's etc and you're well aware of all the above.

Post edited at 20:02
 Simon Yearsley 25 Feb 2023
In reply to DaveHK:As others have already said, “yes” they are quite interesting features. Neil Silver, Malcolm Bass and I nearly fell down one of them after doing Nam Famhairean. I also remember a conversation with Andy N as to whether they were associated with the changes in the volume of ice in Gully of The Gods. There is definitely much less ice ever forming in GoTG than there used to be in the mid 80s, early 90s, and Andy’s proposition was to do with a major shift in the water course due to some big structural changes in the to section of the cliff. Interesting to ponder…. 

 tobyk 25 Feb 2023
In reply to DaveHK:

Haven’t seen these caves in particular , but did find a collect of small caves further to the west along the ridge line, this was about 10years ago but do have a photo. Can imagine the caves are land slip caves in origin, as the ones I went into most certainly were, and probably ancient…although I’m not a geologist either.

 Lankyman 26 Feb 2023
OP DaveHK 01 Mar 2023
In reply to DaveHK:

Photo of the crack in the side of Gully of the Gods. I suppose what you'd want to know is whether this is getting wider!


 Fat Bumbly2 06 Mar 2023
In reply to DaveHK:

Meanwhile in Pembrokeshire...

https://www.theguardian.com/uk-news/2023/mar/06/giant-rats-spark-fears-of-c...

Subterranian Rat Launcher?  Tenby twinned with Hunger City?

Post edited at 22:25

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