Wednesday, 15 November 2017

Mapping Mountains – Trimble Surveys – Moel Siabod and Moelwyn Mawr and Arenig Fawr


17.09.17  Moel Siabod (SH 705 546, only bwlch surveyed), Clogwyn Bwlch y Maen (SH 679 542), Carnedd y Cribau (SH 676 536), Y Cribau (SH 673 533), Arenig Fawr (SH 827 369, bwlch only), Pt. 574.9m (SH 663 500), Pt. 543.5m, Cerrig Cochion (SH 660 508), Cerrig Cochion (SH 662 510) and Cerrig Cochion (SH 663 512)

Clogwyn Bwlch y Maen (SH 679 542)

The central part of the Moelwynion are reminiscent to parts of the Rhinogydd as they are rugged hills with a feel of wilderness compared to their higher but easier underfoot adjoining hills to the south.

Our aim was to visit and survey all necessary hills between Clogwyn Bwlch y Maen in the north and a fine slender ridge of a hill beside Llyn Edno in the south.  We left one car in a lay-by for our descent from Bwlch y Rhediad and continued north to leave the other car just beyond the Pen-y-Gwryd Hotel.

As we walked back on the road toward the footpath giving access to the western ridge of Moel Siabod a blanket of light grey murk slowly pushed its pay up the valley from Capel Curig, a foreteller of light rain that blew in for the first hour or so of the walk.

It was good to be out with Aled again, and today’s walk was a route he’d suggested which if successful would fill in all surveying gaps on the way.  The first objective was the critical bwlch of Moel Siabod which Aled had analysed via LIDAR data, and although I had come prepared with the ten figure grid reference for its position it proved a decidedly boggy affair getting to the point where the Trimble was set up.

Gathering data at the critical bwlch of Moel Siabod

Looking down on the bwlch of Moel Siabod with the Pen-y-Gwryd Hotel on the right

A path heads up from the area of the bwlch toward our first hill of the day; Clogwyn Bwlch y Maen, which is a fine hill dominated by its higher neighbours of Moel Siabod and Carnedd y Cribau.  The mist rolled in as we gained height and light rain fell from a leaden sky, but with an improving forecast we were optimistic for the remainder of the day.

A murky morning as the rain sweeps in

Bi-passing the summit we headed for its connecting bwlch to Moel Siabod and soon determined where its critical point lay, and soon the Trimble was set up gathering its allotted five minutes of data.  Below the double lakes of Llynnau Duweunydd glistened when flashes of sunlight pushed through the easterly cloud bank, all round the higher hills were obscured under a murk, but the morning’s rain had now ceased and slowly the cloud would rise and blue sky appear as we continued heading southward.

Llynnau Duweunydd

Gathering data at the critical bwlch of Clogwyn Bwlch y Maen

The summit of Clogwyn Bwlch y Maen consists of a small greened area a couple of metres from its ridge fence, after the Trimble had gathered data we pressed on to the next connecting bwlch which consisted of a large expanse of moor grass and bog.

Gathering data at the summit of Clogwyn Bwlch y Maen

Gathering data at the critical bwlch of Carnedd y Cribau

Clogwyn Bwlch y Maen with the cloud enshrouded Carneddau in the background

Llynnau Duweunydd with Moel Siabod still in cloud

I’d only visited Carnedd y Cribau once before in August 2002 and remember it as a fine hill, substantial and rocky at its top.  It hasn’t changed!  Although the light grey murk was disappearing the higher hills were still bathed in cloud and further east a cloud blanket shielded all distant views inland, but thankfully even though Carnedd y Cribau was our high point of the day it was free of cloud.  Its summit consists of two large boulders a few metres apart, both were Trimbled, and with the rock still slippy from the recent rain the second one proved a little awkward to stand on top of, thankfully both boulders proved relatively easy to set the Trimble up at their highest point.

The first point surveyed for the summit of Carnedd y Cribau

The view west from the summit of Carnedd y Cribau

The second point surveyed for the summit of Carnedd y Cribau

The southern ridge of Carnedd y Cribau has a 557m map heighted bump on it and we wanted to survey it for potential Uchaf status, although we both thought that the hill only had about 10m of drop.  Once complete we headed down steeply to the next bwlch which is the critical bwlch of Arenig Fawr and which would later in the day also be our descent route, but that would have to wait a few hours as ahead lay Cerrig Cochion.

Gathering data at the critical bwlch of Y Cribau with Aled waiting at its summit

Gathering data at the summit of Y Cribau

Aled heading toward the next bwlch which is that for Arenig Fawr

Whilst at this bwlch Aled set the Trimble up as he’d come prepared with a cunning plan of pressing on to the hill beside Llyn Edno to survey its bwlch and summit, whilst I could leisurely head toward Cerrig Cochion where he would join me doubling back around the eastern part of Moel Meirch.

The upper slopes of Yr Wyddfa bathed in light as the mass of cloud begins to break

Gathering data at the critical bwlch of Arenig Fawr

The shapely profile of Yr Aran

He took all necessary items, including the all-important Trimble, notebook, pen and steel tape, and headed up beside the fence toward Cerrig Cochion, I followed with the intention to meet him on a 540m ringed contour of a bump to the south of Cerrig Cochion which map contours indicated was adjoined to Moel Meirch.

Aled heads off to fall in a bog, I follow and do likewise


Gathering data at the critical bwlch of Pt. 574.9m.  Photo: Aled Williams


Approaching the summit of Pt. 574.9m.  Photo: Aled Williams


Gathering data at the summit of Pt. 574.9m.  Photo: Aled Williams


Llyn Edno.  Photo: Aled Williams

I found the going tough as the bog seemed unrelenting, however delicate my step and long my detour to pass the worst of the bog I stepped on to what I thought to be semi-solid ground and went almost knee deep in black slime.  However, afterward when Aled re-joined me he re-countered that he’d ended up almost waist deep in a bog and only got out as he lunged toward the grass banks and grabbed a hold.

The hazards of trying to cross a bog

If not for the fence line and adjoined path this section of hill would be a wild affair as rock and bog predominate.  I made slow progress and wondered if Aled would reach our rendezvous spot before me.  By now Moel Siabod had cleared of cloud and the warmth of the sun started to edge its way on to the land.  I bi-passed the summit of Cerrig Cochion and headed toward the 540m ringed contour lump to wait for Aled to appear on the path to the east of Moel Meirch, which from this viewpoint looked an impressive lump of rock jutting out of a desolate and beautiful moor.

Moel Siabod

I waited for about 50 minutes, wrapped up in my Goretex shielding the slight breeze and the onset of cold that would inevitably come due to inactivity.  It was a marvellous place to sit and watch the dappled shadow cast across the land.  Behind me to the north the rock strewn summit of Cerrig Cochion reared up sun drenched and then shadowed as the play of light forever changed.  To my south the rock bulk of Moel Meirch reared against a foreground of quiet moor and bog.

Cerrig Cochion


Cerrig Cochion flanked by Moel Siabod to its right

Eventually Aled appeared on the path heading back toward Cerrig Cochion having surveyed the hill beside Llyn Edno, when he arrived he looked slightly dishevelled and recounted his waist deep meeting with the bog.  A couple of minutes from where I had waited was the 540m ring contoured bump that we now wanted to survey, the bwlch was soon complete and as the Trimble gathered its customary five minutes of summit data I joined Aled close to a cairn for a stunning view down and across Llyn Gwynant in the valley below.

Pt. 543.5m, Cerrig Cochion


Gathering data at the critical bwlch of Pt. 543.5m, Cerrig Cochion


Moel Meirch from the summit of Pt. 543.5m, Cerrig Cochion

Gathering data at the summit of Pt. 543.5m, Cerrig Cochion

Our next port of call was the critical bwlch of Cerrig Cochion, thankfully this proved easy to judge where its critical point lay as it was placed in a small canyon with a rocky bulk of a bump immediately above it to the north and the rising slopes of Cerrig Cochion to its south.

Gathering data at the critical bwlch of Cerrig Cochion

It was a slow plod to the summit of Cerrig Cochion and the day’s exertions were beginning to tell.  Once at the summit I positioned the Trimble atop my rucksack aligned with the highest part of rock that I could find at the base of the hill’s summit cairn, and wedged my rucksack in place with rocks as it was delicately placed directly above a small drop.

Aled at the summit of Cerrig Cochion


Just below the summit of Cerrig Cochion - a beautiful and delicate web


The view west from the summit of Cerrig Cochion


Gathering data at the summit of Cerrig Cochion

All that remained from our original surveying plan was a 530m ring contoured bump to the north of the higher Cerrig Cochion summit, we had both visually dismissed this having passed it earlier in the afternoon, and we both decided that it wasn’t worth surveying as we re-joined the path beside the fence for our descent toward the horrendous bog.  However, as we passed its connecting bwlch we stopped, checked the time, and as it was now beautifully sunny with radiant blue sky and hardly a breath of breeze and as we now knew that we had plenty of time for our descent we decided to survey it but only on Aled’s insistence that the minimum two minutes of Data were gathered, I sneaked three minutes at both its bwlch and summit!

The last bwlch survey of the day

Whatever this last bumps survey result it is a fine wee hill with an impressive and attractive summit consisting on an elongated rock where the Trimble was delicately placed collecting summit data.  All that remained was the descent back through the bog and down toward Aled’s car.

The last summit survey of the day

Once past the bog it was a magical descent with early evening low light casting beautiful colour as mist caps descended on the higher mountains.  Away to the west a silver sheened land was now on view as the sun slowly ebbed toward setting.

Late afternoon cloud on the high Glyderau


Heading down to the valley below


Moel Hebog with Llyn Gwynant in the forground

The walk had taken almost ten hours and we had surveyed 17 points in all.  Once back at the car I changed into dry clothes and Aled dropped me off at mine, we waved our goodbyes and I headed down the A5 to treat myself to chips and a number of accompaniments in Betws before heading toward Y Bala and crossing the Y Berwyn.  I stopped near the high point of the road to look west toward coloured sky over the high peaks of Eryri as reds merged with orange and mountain profiles merged with the land.

Sunset over Eryri

Slowly the highlighted reds with the darkened and delicately cloud capped profiles of the hills gave way to subtle blues as the colour ebbed to darkened dusk, a lovely sight to end a day.


   
Survey Result:



Moel Siabod

Summit Height:  872.2m (from subsequent Trimble GeoXH 6000 survey)

Summit Grid Reference:  SH 70524 54631 (from subsequent Trimble GeoXH 6000 survey)

Bwlch Height:  272.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 66044 55603

Drop:  599.9m (P600 Major deletion)

Dominance:  68.78%





Clogwyn Bwlch y Maen

Summit Height:  547.1m (converted to OSGM15)
  
Summit Grid Reference:  SH 67908 54270

Bwlch Height:  525.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 68011 54318

Drop:  21.9m (500m Sub-Twmpau status confirmed)

Dominance:  4.00%





Carnedd y Cribau

Summit Height:  591.5m (converted to OSGM15) 
 
Summit Grid Reference:  SH 67617 53695

Bwlch Height:  507.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 67647 54133

Drop:  84.5m

Dominance:  14.29%





Y Cribau

Summit Height:  556.9m (converted to OSGM15) 
 
Summit Grid Reference:  SH 67383 53333

Bwlch Height:  546.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 67461 53359

Drop:  10.6m (non Uchaf status confirmed)

Dominance:  1.90%





Arenig Fawr

Bwlch Height:  373.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 66532 52254

Drop:  481m

Dominance:  56.28%





Pt. 574.9m

Summit Height:  574.9m (converted to OSGM15)  

Summit Grid Reference:  SH 66301 50001

Bwlch Height:  552.9m (converted to OSGM15)

Bwlch Grid Reference:  SH 66287 50113

Drop:  22.0m (500m Sub-Twmpau status confirmed)

Dominance:  3.83%





Pt. 543.5m, Cerrig Cochion

Summit Height:  543.5m (converted to OSGM15) 
 
Summit Grid Reference:  SH 66011 50831

Bwlch Height:  530.7m (converted to OSGM15)

Bwlch Grid Reference:  SH 66032 50754

Drop:  12.7m (non Uchaf status confirmed)

Dominance:  2.34%





Cerrig Cochion

Summit Height:  548.9m (converted to OSGM15)  

Summit Grid Reference:  SH 66250 51062

Bwlch Height:  524.6m (converted to OSGM15)

Bwlch Grid Reference:  SH 66174 51012

Drop:  24.3m (500m Sub-Twmpau status confirmed)

Dominance:  4.42%





Cerrig Cochion

Summit Height:  533.0m (converted to OSGM15) 
 
Summit Grid Reference:  SH 66395 51267

Bwlch Height:  519.8m (converted to OSGM15)

Bwlch Grid Reference:  SH 66361 51202

Drop:  13.1m (non Uchaf status confirmed)

Dominance:  2.47%












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