Mapping Mountains – Trimble Surveys – Y Llethr

 

24.08.21  Rhinog Fawr (only bwlch surveyed, SH 657 290), Rhinog Fach (SH 664 270) and Pt. 558.3m (SN 661 267) 

Rhinog Fach (SH 664 270)

There are many upland areas in Wales that captivate me and draw me back time and again.  The trackways of the Radnorshire hills on a bright and crisp spring morning with skylarks singing overhead or the tranquil surrounds of the open Elenydd in autumn, but few can compare to the quality of the northern Rhinogydd, these hills are rugged and unforgiving and form a barrier between the land to their east and the coastal plain to their west. 

For many years my walking was dominated by the Welsh 2,000ft hills with many repeated ascents, nowadays it is mainly on lower heighted hills, and to an extent is led by my surveying.  However, when opportunity arises to visit those higher 2,000ft’s it is one not to miss. 

Today I wanted to visit a hill I had been up on 18 previous occasions and one that was long overdue an accurate survey.  The hill is Rhinog Fach which is positioned in the northern Rhinogydd. 

Rhinog Fach is currently listed with an estimated c 148m of drop, just a tantalising 2m short of the 150m drop criterion for Marilyn status.  Over recent years Alan Dawson; the hill list compiler of the Marilyns and author of the Relative Hills of Britain book, has surveyed many hills marginal to the 150m drop criterion.  The majority of these hills are in Scotland, but there is one hill in Wales that also requires an accurate survey to determine its drop value and status, and that hill is Rhinog Fach. 

With a high pressure system centred over the country giving relatively dry conditions, albeit with drizzly morning’s around the eastern part of Mid Wales, and with a forecast of west is best and lots of sun symbols on the Trawsfynydd Met Office web page, I headed toward Coed y Brenin to park at the end of a narrow paved road that heads west from the busy A470.  I knew even before seeing the Rhinogydd that their higher tops would be immersed in morning clag, as the tops of all other hills heading west from Welshpool were cloaked in cloud.  However, I was in no rush and leaving my car I proceeded to slowly make my way through the undergrowth constituting the public footpath toward Graigddu-isaf, an old farm house that is now an Airbnb let. 

The old farmhouse is positioned in a small clearing with the forest track leading past it; I was soon on it walking along the forest track heading south.  Overhead the sky was grey with a constant cloud blanket that stretched the full width of Wales.  But I knew as time progressed the cloud would rise and if the same weather condition were applicable to this part of Wales, as to Welshpool, the sun would break through by early afternoon. 

I lazily plodded up the continuation of the forest track, eventually emerging at a sign that pointed confidently toward Bwlch Drws Ardudwy.  At this junction the conifer infestation had been felled giving an unobstructed view of the two Rhinog hills; Fawr and Fach; both heading skyward in to the morning murk. 

The way to the bwlch with Rhinog Fach enshrouded in early morning clag

A gravelled path led from the junction up to a gate and the continuation of a path on to the open hillside.  It was good to be back here, although this was a route I had used in the past, my favoured route of ascent for Rhinog Fach is from the west via Cwm Nantcol, this gives an open view of the hills from a beautiful high valley, but the forest route has a higher start and is much easier to get to when driving in from the east. 

My first planned survey of the day was the bwlch of Rhinog Fawr and as I walked up the path heading toward it, the open nature of the hillside quickly closed in, with the boulder strewn slopes of Rhinog Fawr rising upward on my right and the steep slopes of Rhinog Fach doing likewise on my left.  It was a humbling place to find myself. 

The steep path leading up Rhing Fach from Bwlch Drws Ardudwy

The bwlch position for Rhinog Fawr was relatively easy to pinpoint and soon the Trimble was set up atop my rucksack, the measurement offset between its internal antenna and the ground at its base noted and once the 0.1m accuracy level was attained before data should be logged, I set it to gather data and sat behind a rock to wait the allotted five minutes. 

Gathering data at the bwlch of Rhinog Fawr

Once the first data set of the day was gathered and stored, I packed the Trimble away and peered up at the horrendously steep slope I had somehow voluntarily chosen as my ascent route.  This route is uncompromising and just heads up through heather and rock.  It looked intimidating. 

The cloud base was still relatively low and would remain so for another 90 minutes, therefore I was in no rush and with the steep slope immediately in front of me I made slow, but steady progress up it.  I rested frequently and looked out east where the cloud still hung to all high hills.  Behind me the cloud danced on the upper section of Rhinog Fawr with the brisk breeze whisking it across the summit rocks. 

Eventually the steepest section of the ascent was behind me and cresting a rise the upper part of the hill bulged up in front.  This resembles a cone of a hill seemingly plonked on top of what is already quite a substantial land mass, thankfully by the time I was looking up at this scene the cloud base was slowly edging ever higher and the route ahead was clear. 

The path eventually crests the northern ridge of Rhinog Fach, at this point I had just walked up in to the mist which was being skimmed across the hill by a strengthening breeze, so much so that I contemplated stopping to put on my one skin jacket as my arms were getting quickly chilled, I persevered without and continued following the path toward the summit of the hill. 

The summit of Rhinog Fach consists of a small protruding rock about 2 metres from the base of an untidy cairn.  I quickly set the Trimble up aligned with the highest part of the rock and set it to gather data.  I was thankful that the summit was easy to identify as I wondered if I would have to take a number of data sets from various points surrounding it.  But to compare survey results I wanted to gather a second data set with the Trimble now positioned over the highest rock and on my rucksack.  As I was setting the equipment up I was joined by two walkers, one from Llanelli and the other from Caerffili who were bagging hills around the Rhinogydd for a few days based in Maentwrog.  As the Trimble gathered the second summit data set we sat below the equipment chatting about the hills. 

Gathering data at the summit of Rhinog Fach

To have wanted to survey this hill for many years and many other surveys seemingly always getting in the way, and now to finally be here on its summit with the Trimble quietly beeping away gathering individual datum points, was both a relief and a joy.  As I sat glimmers of sunshine fed across the land toward the coast to the west.  It felt like being on top of the world, perched on this boulder strewn hill, sitting on a rock looking out at an ever evolving view.  As I turned to close the Trimble down I suddenly realised that the cloud base was now above the summit, which boded well for the remainder of the walk. 

I walked part of the way down toward the connecting bwlch in the company of the two walkers from south Wales, but as I opted for my normal descent route on the western side of the stone wall, they reversed their inward route on its eastern side.  We met again down on leveller ground and walked to the bwlch together.  They still had a long day ahead with Y Llethr, Diffwys and a walk back in to Cwm Nantcol ahead, whilst I now concentrated on the bwlch adjoined to Rhinog Fach. 

Y Llethr rising above Llyn Hywel

I was surprised to find that ground on the eastern side of the stone wall that crosses the bwlch was higher than on its western side, imagining that the wall would cross the actual bwlch.  Therefore I concentrated my efforts on a small area of land just to the east of the stone wall, taking three data sets in all, two on the hill to hill traverse and one on the valley to valley traverse. 

I was at the bwlch for over 40 minutes and watched the two South Walian walkers crest the upper part of Y Llethr and disappear from view.  By now the full extent of Rhinog Fach was on view and would remain so for the remainder of the walk. 

Gathering the first of three data sets on the area of the bwlch

Happy with my efforts at the bwlch I packed the Trimble away, scrambled back over the wall and walked a short distance back toward Rhinog Fach to connect with the path leading down to the northern shore of Llyn Hywel, which I’ve heard by many to be the most beautiful mountain lake in Wales, I would not argue otherwise. 

The path led to the outflow of the lake, I now wanted to survey the small prominence hill that overlooks Llyn Hywel from the lake’s western edge and therefore followed the continuation of the path around the western shore, only leaving it to head up toward the connecting bwlch of the hill.  This bwlch was typical northern Rhinogydd country as it has large boulders strewn around it, many amongst reed grassed tussocks.  I soon picked my preferred spot and soon the Trimble was gathering its seventh data set of the day. 

Gathering data at the bwlch of Pt. 558.3m

Once the Trimble was closed down and packed away I followed a narrow path leading toward the summit, which is crowned by a flattish outcrop of rock.  By now the breeze was blowing across the lake and therefore I placed the Trimble on the ground aligned with the highest part of the summit rock.  During data collection the sun finally broke through as the cloud that had lingered all day began to break, and this gave me wonderful colour for the remainder of the walk. 

Gathering data at the summit of Pt. 558.3m (SH 661 267)

All that remained was to follow paths back to the forest track.  I took my time and enjoyed the wonderful mountain scenery with Rhinog Fawr looking a beast of hill from this perspective.  Its profile a great lump of rock and heather, from this vantage point Rhinog Fawr must be one of the most impressive hills that Wales has to offer.  I savoured this view, as I did when I left the shore of Llyn Hywel, it had been 16 years since I last stood on the summit of Rhinog Fach and it is now reaching a point that when on a higher hill I wonder if I will ever return.  The afternoon sunshine, with the purple of heather and the rusted tips of reed grass just starting to turn and that stunning profile of Rhinog Fawr was to be remembered and if this is the last time I venture to this particular domain, it gave me a fine memory to implant in my mind’s eye, one that will remain with me for a long time to come. 

The route back toward Llyn Hywel with Y Llethr in the background

The mountain goats of the northern Rhinogydd

Leaving the outflow of Llyn Hywel I connected with the good path leading down in to Cwm Nantcol, on the way I met two backpackers heading up to the lake to overnight.  They were from Cardiff and we stopped and chatted for ten minutes or so.  I enjoy meeting people when on the hill and the conversation that ensues, this time it also gave me a rest as my energy levels were beginning to plummet.  A little lower I met a man from Manchester who was doing the full traverse of the Rhinogydd, his father lived in Harlech and was picking him up in Barmouth later in the evening, he still had a long way to go. 

Rhinog Fawr with Llyn Cwmhosan in the foreground

Arriving in the upper reaches of Cwm Nantcol was a blessing as my knees no longer had any steep descent to contend with.  However, it also meant that I now had to veer right and reclaim lost height to crest the upper part of Bwlch Drws Ardudwy, this I found a struggle and stopped an inordinate amount of time to recover my breath.  My energy levels had completely plummeted; I sat frequently, ate a banana and a club biscuit and struggled on, eventually reaching a prominent cairn signifying the top of the path overlooking the bwlch. 

The wall leading to Bwlch Drws Ardudwy

Before leaving the bwlch I peered up at that horrendously steep slope I had tackled earlier in the morning, leading toward the summit of Rhinog Fach.  I will probably never have the misfortune to head up it again.  I found this a comforting thought. 

I slowly continued on the path leading back to the felled section of forestry and the gravelled path leading down to the junction with the forest track.  On the way I watched a multitude of butterflies feeding on buddleia plants, which added their light purples to the bloom of heather and the red berries of the rowan.  I stopped to watch and take a few photographs and looked back toward the hill, now free of clag and bathed in late afternoon sunshine. 

Jen, Rog and Archie Lewins

The forest track gave an easy way back to my car, and one that was to get easier as when I approached the forest gate across the track there were four cars parked on the opposite side with a number of people beside them.  When I arrived I said my hello’s and within a few minutes was sitting in a car with Jen, Rog and Archie Lewins being driven the remaining distance on the forest track back to my car.  This was a kind gesture given to a tired hill walker, thank you. 

 

Survey Result:

 

Rhinog Fawr

Summit Height:  720m (spot height)

Summit Grid Reference:  SH 65700 29012 (hand-held GPS via DoBIH) 

Bwlch Height:  352.6m (Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 66446 28164 (Trimble GeoXH 6000)

Drop:  367m (spot height summit and Trimble GeoXH 6000 bwlch)

Dominance:  51.02% (spot height summit and Trimble GeoXH 6000 bwlch )

 

 

Rhinog Fach

Summit Height:  711.6m (converted to OSGM15)

Summit Grid Reference:  SH 66485 27017   

Bwlch Height:  560.6m (converted to OSGM15)

Bwlch Grid Reference:  SH 66561 26533

Drop:  151.0m (Submarilyn reclassified to Marilyn)

Dominance:  21.22%

 

 

Pt. 558.3m

Summit Height:  558.3m (converted to OSGM15)

Summit Grid Reference:  SH 66160 26783   

Bwlch Height:  535.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 66225 26636

Drop:  23.1m

Dominance:  4.13%

 

 

For further details please consult the Trimble Survey Spreadsheet