Sunday, 23 February 2025

Mapping Mountains – Trimble Surveys – Arenig Fawr


18.01.25  Pt. 513.4m (SH 775 244) and Graig Fach (SH 792 249) 

Graig Fach (SH 792 249)

At 7.00am I was on my laptop looking at an image of a sun symbol that according to the Met Office would give the area around Bala continuous sunshine from approximately 9.00am – 3.00pm.  I left Welshpool shortly afterward, heading west to meet Aled on the outskirts of Dolgellau.  The skies were particularly grey during this journey with cloud cover on the higher tops as I drove through Dinas Mawddwy.  I hoped the promised sunshine would materialise, unfortunately it didn’t.  However, the hills we visited were free of cloud, and albeit slightly chilly the conditions were good.

The walk was suggested by Aled, who had two sub hills on his radar, both of which LIDAR gives as just under 10m of drop.  I had surveyed one of them many years ago with my old wooden staff as having just over this designated drop value.  Both hills were in the vicinity of their higher neighbour; Rhobell Fawr.

Meeting Aled, we left his car in a lay-by close to the Dolgellau bi-pass and continued in mine with Aled navigating to the narrow minor road leading off of the A494 road as it heads north-eastward toward Bala.  The minor road joins others in this area that haphazardly meanders around this part of the country.  We soon turned right and headed up in to the hills, only stopping to open a number of gates.  I knew from past visits that the paved section leads directly on to a good forest track and this can be followed to its highest point between Dduallt and Rhobell Fawr.  However, I hadn’t been this way in a number of years and the forest track leading from the end of the paved minor road is now rough, it is still driveable, but be warned, as it’s now a zig zag affair with lots of eroded sections.  We made it up without any undue difficulty, but with hindsite it would be best to park lower down where the forest track intersects with another track. 

Heading for the hill

We had two hills to aim for and each could be accessed from another forest track that headed westward and then south from where I parked the car.  This track was open in its upper part affording views across the intervening valleys to the last remnants of lingering snow on the higher hills around Cadair Idris and the Aran.  However, a blanket of greyed cloud shielded these higher tops. 

The rock strewn slopes immediately below Graig Fach

The track descended to an entrance in to the forest, on our way we were passed by eleven trail bikes as they spluttered their way through the muddied sections.  On our way back Aled found one of their number plates on the edge of the track.  This must be great fun if in to off roading trail bikes, but for the hill walker the noise and fumes distract from an otherwise tranquil scene, and those on the hill course undue damage to the landscape.

When the track entered the forest we accessed the open hillside to its west through a gate.  I then proceeded to follow Aled as he headed up toward our first hill of the day.  This could be seen on the horizon forming a good looking small upthrust on the wildly situated ridge above.  This ridge descends south-westward from the summit of Rhobell Fawr and then swings south-eastward to crest the summit of Moel Cors y Garnedd. 

The first hill surveyed is the bump on the ridge on the left of this photograph

Nearing the summit I had lingered behind and watched as Aled crested the high point, a few minutes later and I was there beside him.  It proved a wonderful summit to be on, nestled in a wild area of open moor with just an occasional robust stone wall that could be used for navigational purposes.

The Trimble was soon placed on its high point, which consists of a grassy knoll atop a small outcrop of rock.  As it gathered data I sat with Aled having a bite to eat and looked around at the wildness of the ridge as it continued over a number of small tops, with the continuation north-eastward up in to cloud which hugged the upper reaches of Rhobell Fawr. 

Gathering data at the summit of the first hill surveyed (SH 775 244)

Once allotted data were gathered and stored, I closed the equipment down, packed it away and followed Aled down to its connecting bwlch, which today consisted of a muddied puddle amongst a winter bog.  Prior to visiting, Aled had LIARed both hills and although we scrutinised the area of the bwlch by eye, we relied upon the ten figure grid reference generated by Aled’s LIDAR analysis to zero in to the critical point of the bwlch.  Again the Trimble was soon set up, this time on my rucksack to give it elevation above its immediate surrounds.  It didn’t seem to enjoy this position as it screeched during data collection, indicating the 0.1m mark that should be achieved before data is gathered had dropped off.  In instances like this I usually allow the equipment to gather more than the five minutes of data that is the norm, this usually gives it chance to attain the required 0.1m accuracy level again. 

Gathering data at the bwlch of the first hill surveyed

Leaving the bwlch I followed Aled as he reversed our inward route back to the edge of the forest and our track back toward the next hill; Graig Fach, and which eventually would lead to the awaiting car.  By now I had slowed and was consious that I was holding Aled back, so he took the Trimble and skipped off up the track to tackle Graig Fach on his own, leaving me to plod back on the track under this hill’s impressive southerly facade. 

Aled heading off toward Graig Fach

I stopped at each gate and looked back down the track and across to the hills beyond.  It was a marvellous scene of conifer, rock, open hill, wild moor and greyness.  As I continued up the track I could now see Aled on top, at this point a forest gate gave a slight sound as it was opened and closed; this was just to the south of where I now was.  A slight figure emerged on to the hillside.  Aled would later confirm it was a woman who was navigating with the aid of her mobile phone and was obviously heading up to the summit of Rhobell Fawr.  As I watched she made good progress up over the track I was on and continued on the steepening ground at the base of Graig Fach, before disappearing around its flank.  My view of the hill was also just about to disappear as I continued up the track with an intervening ridge obstructing any further view of this rocky peak. 

Gathering data at the summit of Graig Fach (SH 792 249).  Photo: Aled Williams

Arriving back at the car I changed and waited for Aled.  A woman walking a dog soon appeared on the main track; she stopped and chatted for quite some time.  She lived in one of the farms at the bottom of the track we had used with her husband coming from Welshpool before moving to Dolgellau at a young age.  Aled soon appeared and we continued our talk as he got his boots off.  Another woman then appeared on the main track, she said hello and headed off on the track we had used.  It was positively busy in this seldom visited area of Wales!

It had been a good day on the hill, visiting a place I had not been to for a number of years, and although due to the grey cloud cover no higher tops were on view, it was good to be out in such a wild area of land.

 

Survey Result: 

 

Pt. 513.4m

Summit Height:  513.4m (converted to OSGM15)

Summit Grid Reference:  SH 77569 24456

Bwlch Height:  503.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 77538 24513

Drop:  9.9m

Dominance:  1.92%

 

 

Graig Fach

Summit Height:  511.0m (converted to OSGM15)

Summit Grid Reference:  SH 79262 24920

Bwlch Height:  501.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 79278 24975

Drop:  10.0m (Welsh Highland Sub Reinstatement)

Dominance:  1.96%

 

 

For further details please consult the Trimble Survey Spreadsheet 

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