Wednesday, 12 March 2014

Mapping Mountains – Trimble Surveys – Carneddau

10.03.14  Moel Faban (SH 634 679), Y Gurn (SH 647 687), Moel Wnion (SH 649 697), Trwsgl (SH 664 679), Bera Mawr (SH 674 682) and Bera Bach (SH 672 677) 

Y Gurn (SH 647 687)
With a high pressure system firmly established over the country and the forecast of sunshine for the west of Wales I decided to visit some old friends in the Carneddau.  I parked above Bethesda (SH 630 672) at the end of the paved road next to a row of terraced houses.  Parking is dependent upon the use of the car parking area by the residents of the houses.  Otherwise parking can be found lower down in Bethesda.

Breakfast time in Bethesda
From the end of the paved road a green lane leads up through a kissing gate and out on to open hill side where a good green path heads up toward the summit of Moel Faban (SH 634 679).

The summit has a large cairn overlooking the southern lands, whilst three ancient megalithic cairns are lined heading north, all have been reconstructed in to walkers shelters.

I had a brief look around the first cairn encountered for high embedded rocks that could be deemed as the ‘natural’ high point of the hill, but once my eye had looked over the summit area I had no hesitation in deciding that the ‘natural’ high point must be a large erratic boulder overlooking Ynys Môn and the sea.  I jumped on top (haphazardly clambered up!) and then placed the Trimble on the high point and awaited its ten minutes of data collection.

Moel Faban (SH 634 679) summit with the Trimble gathering data on the large boulder on the right of the photograph
My initial intention was to visit the higher hills before finishing up on the lower and leaving Moel Faban as the last.  But as Pen yr Ole Wen and Carnedd Dafydd were bathed in sunshine and clear skies, this part of the north-western Carneddau was facing directly in to the northern breeze, and however slight this was, it meant that Carnedd Llywelyn and the lower hills of Bera Mawr, Bera Bach and Trwsgl were all under a dark grey murk.  Therefore I swapped the route from anti-clockwise to clockwise.  This at least meant the higher hills of the day’s walk now had time for the late morning’s and early afternoon’s warmth of the sun to burn off any unwanted cloud.

As I waited on the summit area of Moel Faban for the Trimble to accumulate its required data I looked out on dramatic light as wisps of cloud left the higher ridges of the Glyderau.  To the north-west Ynys Môn had banks of dark cloud being accentuated by the bright early morning sunshine.  Richness of colour can sometimes enthuse and those few minutes on Moel Faban were no exception.

I planned to survey seven hills during the day with data taken at each summit and bwlch.  I hoped to gather ten minutes of data at each, but realising that this may mean being still on the hill as darkness began to fall I decided to try and get ten minutes of data from each summit and five from each bwlch.

The bwlch between Moel Faban and Y Gurn (SH 647 687) is narrow on the hill to hill traverse as steep grassed land sweeps down to the crossing.  I again chose my spot for data collection and once five minutes of data was gathered I proceeded on my way up the steepening slopes toward Y Gurn.

This hill has a distinct shapely profile when viewed from all sides and although its neighbour of Moel Wnion somewhat dwarfs it in height and bulk it is by far the better hill.  I’d only visited once before and as I walked up its last rock strew slopes I wondered if the whole upper part of the hill was an ancient cairn.  It isn’t but the summit has a large wind shelter at its highest point.  This made surveying with the Trimble a little difficult.  I spent a few minutes testing a number of protruding rocks, many were found to move when kicked or shaken.  The one that looked to be the highest ‘natural’ embedded rock was partly under the wind shelter and the Trimble may not have taken to being positioned immediately below a 4ft wall of rock, so I moved it to an adjacent embedded rock that was about 2cm lower in height.

The summit of Y Gurn (SH 647 687)
By now the higher hills were showing signs that their early morning grey murk had been swept away and as I visited the connecting bwlch with Moel Wnion the early morning crispness had been replaced by the warmth of the sun.

After more bwlch data was collected I followed a vehicle track up to the summit of Moel Wnion where another wind shelter greeted me.  This one has the remains of the base of a trig pillar in it.  According to the OS Trig Database the pillar was destroyed in 2003.

I assessed the surrounding ground and chose the highest piece of grassed land on the eastern side of the wind shelter in favour of a boulder on the western side.  Another ten minutes of data was stored and away I went, checking my watch and trying to judge how long each hill was going to take to survey.  I’d worked out that spending 75 minutes on each hill meant that I’d get back to the car at approximately 5.00pm, and as the weather was set fine it meant I’d have at least an hour spare before darkness set in.  By the time I was heading down to the bwlch of Moel Wnion it was 11.15am and I’d been on the move for three hours and three hills had been surveyed.  This at least gave me peace of mind that I’d now got another 45 minutes leeway.

The summit of Moel Wnion (SH 649 697)
After another data set had been gathered at the critical bwlch of Moel Wnion I had an approximate 900ft of ascent to the next summit of Trwsgl.  A good path led up this part of the hill on to the broad ridge that connects Trwsgl with Gurn Wigau.  This path gains height and heads toward the higher peaks of the Carneddau, missing out on the delights of the next four hills.

Y Gurn from the critical bwlch of Moel Wnion

Trwsgl (SH 664 679) from the path toward Bera Bach
The summit area of Trwsgl is made up of a large wind shelter and three cairns, one large, one medium sized and one untidy sized.  I went from one high rock to another, slowly working my way in to the heart of the high point of the hill, some of this was done on my belly as I lay down and looked through my expensive optical sight (99p spirit level), this surveying implement caused one person to remark ‘that’s just rubbish’ when he first cast eyes upon it.  However, it does seem to work rather well and it can fit in the smallest of pockets.

I found what I deemed to be the highest embedded rock and then stood back and wondered how on earth I was supposed to set the Trimble up on it to gather data.  I tried it on the rock and it miraculously defied gravity and stuck to it.  Just to be on the safe side I constructed a small tower of rock underneath it in an attempt to give it some support.  Once the ‘Log’ button was activated to gather data I backed away and looked out on the higher mountains to my south-east and toward my next objective; Bera Mawr.

The summit area of Trwsgl with (L - R) Llwytmor (SH 689 692), Bera Mawr (SH 674 682), Foel Fras (SH 696 681) and Bera Bach (SH 672 677) in the background
The Trimble defying gravity on the highest embedded rock I could find on the summit of Trwsgl (SH 664 679)
Before getting to grips with the summit of Bera Mawr I needed to gather data at the critical bwlch of Trwsgl.  This area comprises a number of small pools and as the Trimble was activated to gather its five minutes of data I quietly watched two wild Carneddau ponies walking toward one of the pools for a drink. 

The wild Carneddau pony is a rare breed and one of the delights of the mountain range
In March and April 2013 it is estimated that around 100 of these ponies died due to the freezing conditions on the mountain range, they are gathered each year to assess their numbers and health and although locals feared for their numbers last year, this annual gathering brought down around 160 breeding mares.  They are a well-established feature of this hill range and as one of last year’s gatherers said when interviewed by the BBC ‘They have never been financially viable but we keep them for their beauty and their ability to provide balance on the mountain.’

As the ponies rejoined others a little lower on the hill side I made my way around the rocky southern side of Bera Bach toward the impressive summit of Bera Mawr (SH 674 682).  I was beginning to think of these hills as old friends, first encountered over 25 years ago, often visited since, but before today only once in the last twelve years.

Bera Mawr (SH 674 682)
Bera Mawr is listed as a Sim and Hewitt with 30m of drop and a Pumau and Uchafion with an estimated 31m of drop.  The summit is impressive and consists of a jumble of rock, much of it pointed and big.

Once the customary bwlch data had been stored I approached the rock, slowly making progress up and around to the right, picking out grassy areas amongst the piles of boulders.  Higher up near to the summit the hill requires hands on rock to get to the top.  Once reached I wondered how the Trimble was going to be positioned adjacent to the very highest part of the highest rock, fortunately the highest rock has a convenient plinth ready made for something the length of a Trimble GeoXH 6000 to fit on with its internal antenna comfortingly sitting on the high point and its rear end rather snuggly sitting on the rock plinth below.  If not for this I may have had to hold the Trimble in place, which wouldn’t have been ideal.  I was also lucky as there was very little breeze, and any significant wind may have toppled an expensive bit of surveying equipment to the depths of rock Trimble death below!  All I had to do was keep an eye on it without over balancing on my delicate perch.

Bera Mawr above its critical bwlch
Made to measure - the Trimble GeoXH 6000 on the high point of Bera Mawr (SH 674 682)
As I made my way down the rock cascade to safer ground below I knew that I’d also get down from the hills before darkness overtook me, a very comforting thought.  Next stop was the critical bwlch of Bera Bach which proved another area of land made up of small pools.

The bwlch of Bera Bach with its summit in the background on right
Ahead was another rocky summit, this time Bera Bach, the higher although lesser of the two Bera peaks of the Carneddau.  This time the Trimble had to balance across two pointed rocks and be wedged in place with more rock from below.  I hoped the whole thing would not crumble and send the Trimble bouncing six foot down on to the rock.  It survived and once another ten minutes of summit data had been gathered I made my way down the southern rocky part of the hill and back on to the path that I was on earlier in the day.

The summit of Bera Bach (SH 672 677)
As I approached Trwsgl I took more photos of the ponies as they lay in the afternoon sun with the higher Bera peaks as a backdrop.  To the south-east Carnedd Llywelyn was now highlighted by the late afternoon sunshine with streaks of winter snow on its upper western edge, an impressive hill.

Carnedd Llywelyn (SH 683 643)
The path bi-passes Trwsgl and heads down toward Gurn Wigau; my last summit of the day and one that meant that I had only 33 hills left for my 18th round of the Welsh Nuttalls (not forgetting the one left for my 17th!).  As I arrived at its bwlch a motorbike chortled its familiar and invasive sound as it whizzed past on the path on its fast journey toward Bethesda; the first time I’ve seen any form of motorised vehicle on the Carneddau.

An unfortunate sight on some hills
The summit of Gurn Wigau (SH 654 675) with Moel Wnion (SH 649 697) in background on left
Beyond Gurn Wigau I embraced that trance like state when one’s mind wanders and walking is done on semi-automatic.  The route down headed south-west from the last summit of the day crossing the Afon Ffrydlas with the profile of Y Gurn at the head of the valley bathed in fawn colour and edged by blue sky.  A marvellous last memory of a great day on the hill.

Y Gurn (SH 647 687) from the Afon Ffrydlas

Survey Result:

Moel Faban

Summit Height:  408.7m (converted to OSGM15)

Summit Grid Reference:  SH 63418 67984

Bwlch Height:  362.7m (converted to OSGM15)

Bwlch Grid Reference:  SH 63756 68225

Drop:  46.0m

Dominance:  11.26%  

Y Gurn

Summit Height:  541.3m (converted to OSGM15)

Summit Grid Reference:  SH 64739 68792

Bwlch Height:  496.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 64871 69070

Drop:  45.1m

Dominance:  8.33%  

Moel Wnion

Summit Height:  579.9m (converted to OSGM15)

Summit Grid Reference:  SH 64972 69708

Bwlch Height:  476.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 65201 68803

Drop:  103.6m (Hump status confirmed) 

Dominance:  17.87%

Trwsgl (converted to OSGM15) (significant name change)

Summit Height:  756.9m

Summit Grid Reference:  SH 66387 67984

Bwlch Height:  720.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 66787 67818

Drop:  36.6m (700m Twmpau and Simm status confirmed)

Dominance:  4.84%

Bera Mawr

Summit Height:  793.6m (converted to OSGM15, Trimble GeoXH 6000) 793.7m (converted to OSGM15, Leica RX1250)

Summit Grid Reference:  SH 67482 68270 (Trimble GeoXH 6000) SH 67482 68271 (Leica RX1250)

Bwlch Height:  763.9m (converted to OSGM15)

Bwlch Grid Reference:  SH 67513 68149

Drop:  29.7m (Trimble GeoXH 6000) 29.8m (Leica RX1250 summit and Trimble GeoXH 6000 bwlch) (700m Twmpau reclassified to 700m Sub-Twmpau and Simm reclassifiied to Subsimm and Hewitt reclassified to Subhewitt) 

Dominance:  3.76%

Bera Bach

Summit Height:  806.4m (converted to OSGM15, Trimble GeoXH 6000) 806.5m (converted to OSGM15, Leica RX1250)

Summit Grid Reference:  SH 67209 67772 (Trimble GeoXH 6000) SH 67209 67772 (Leica RX1250) 

Bwlch Height:  788.8m (converted to OSGM15, Trimble GeoXH 6000) 788.8m (converted to OSGM15, Leica RX1250)

Bwlch Grid Reference:  SH 67579 67609 (Trimble GeoXH 6000) SH 67582 67608 (Leica RX1250)

Drop:  17.6m (Trimble GeoXH 6000) 17.8m (Leica RX1250) (Pellennig, Uchaf and Nuttall status confirmed)  

Dominance:  2.18% (Trimble GeoXH 6000) 2.20% (Leica RX1250)

For further details please consult the Trimble survey spreadsheet click {here}

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