Showing posts with label Hewitts. Show all posts
Showing posts with label Hewitts. Show all posts

Sunday, 1 December 2024

Mapping Mountains – Trimble Surveys – Crib Goch

 

05.10.24  Crib Goch (SH 624 551), Pt. 914.6m (SH 623 551), Pt. 901.8m (SH 622 551), Pt. 906.2m (SH 619 551), Pt. 563.0m (SH 638 551) and Carreg Gwalch (SH 642 552) 

The early birds had already gathered at Pen y Pàs, but pure thriftiness, or perhaps self-imposed meanness, had destined my course past them for a lower starting point near the bottom of Bwlch Llanberis.  As I wearily stumbled out of the car, I spotted lights up on the darkened skyline as an even earlier bird traversed along the north ridge of Crib Goch.  This mountain was the primary surveying objective for the day. 

Sunrise.  Photo: Aled Williams

A steep ascent was tempered by scenes of sunrise, with the silhouette of a cloud-capped Moel Siabod beautifully framed by the walls of Y Pàs, its narrow road conspicuously snaking up the valley below.  Periodic rests allowed me to appreciate the ruggedness of these mountains, vast slopes riddled with rock features of various character.  I marvelled at these being the workplaces of the shepherds, the true “mountain men”. 

Base of the north ridge.  Photo: Aled Williams

I had now arrived at the base of the north ridge.  A fair-weather day had been promised but with 30mph wind speeds and these were most definitely present with occasional blusterier spells.  As I ventured onto the start of the arete, I took note of the greasy rocks, not yet dried from the dampening effects of the overnight mists.

The lower arete.  Photo: Aled Williams

Before continuing further I decided to prepare myself for surveying, in case the winds made it difficult to retrieve the various pieces of equipment whilst on the ridge.  The downside of this was that the collection of objects hanging around my neck and stuffed into pockets restricted movement and tended towards imbalance!  I would have to take the traverse carefully and slowly. 

The upper arete.  Photo: Aled Williams

Despite a few uncomfortable blasts from the wind, the ascent of the north ridge went by without incident and I soon found myself at the eastern end of the summit arete, where a few flocks of those early birds were resting having ascended via the east ridge.  I decided that it would be best to go on before them, thus giving me the opportunity to set up the Trimble GeoXH 6000 while they traversed past me, meaning that data collection could then occur without interference from passers-by. 

The summit arete.  Photo: Aled Williams

My memory of the highest point was thankfully incorrect and it proved a relatively sheltered and safe position to spend what would otherwise be a disproportionate amount of time on such an airy summit.  I immediately started to collect 5 minutes of data once the first group of people passed by and was not interrupted by others.  I packed away the equipment happy with the thought that the summit of Crib Goch had now been surveyed. 

Surveying the summit of Crib Goch.  Photo: Aled Williams

The next objective was to survey the bwlch and then the summit of the highest of Crib Goch’s famous pinnacles.  Both points were easily surveyed, with an Abney level being used to locate the highest spike of rock atop the pinnacle. 

A window on the world.  Photo: Aled Williams

As I packed away the equipment atop the highest pinnacle, numerous groups were now making their way along the summit arete.  It was getting busier and this would make surveying the lowest of the pinnacles very difficult. 

The highest of the pinnacles.  Photo: Aled Williams

The problem became apparent once I arrived at the bwlch of the lowest pinnacle.  Its position was a nick between two rocks, exactly at the start of the easiest route that allows passage up and over the pinnacle.  The best approach was to survey it in a time window between the groups of people.  Unfortunately, the tight confines of the bwlch impacted the Trimble’s ability to reach its required accuracy level for measurement.  Just as it was close to reaching this level, a group of people would pass and it would shoot back up to inaccurate levels again! 

The problematic tight bwlch of the lower pinnacle.  Photo: Aled Williams

After a frustrating 45 minutes at the bwlch, data was eventually collected.  I quickly scrambled to the top of the lowest pinnacle and located the highest spike of rock through use of an Abney level.  In contrast, this survey went smoothly and within 10 minutes it had been completed. 

Surveying the summit of the lowest pinnacle.  Photo: Aled Williams

I descended to Bwlch Coch and headed straight to the bwlch of the next top to be surveyed (Pt. 906.2m at SH 619 551).  This was formerly listed as a Welsh Highlands Sub, but was deleted in March 2023 following LIDAR analysis that gave the top only 9.8m of drop.  Given the highly marginal nature of the LIDAR result, this was a priority survey to complete. 

The bwlch of Pt. 906.2m.  Photo: Aled Williams

As the Trimble gathered data, I sat on the grassy edge looking down to Cwmglas Mawr.  The vista of lakes and peaks beyond was stunning, as was the one behind me of Clogwyn y Garnedd and Lliwedd.  A short walk along the narrow ridge of the top brought me to the summit rocks and the Trimble was duly positioned for 5 minutes of measurement. 

Surveying the summit of Pt. 906.2m.  Photo: Aled Williams

After packing up the equipment I headed back to Bwlch Coch, taking the unpleasantly steep descent to Llwybr Pyg during the height of the midday heat.  My final objectives of the day were two Welsh Highland Subs found on the ridge between Bwlch y Moch and Pen y Pàs: Pt. 563.3m and Carreg Gwalch.  These surveys were completed efficiently with not a single walker met along the entire length of the pleasant undulating ridge that joins the two tops together.  All that remained of an excellent day’s surveying was the long plod back to the car.

Pt. 563.0m and Carreg Gwalch.  Photo: Aled Williams.


Survey Result: 

 

Crib Goch

Summit Height:  924.0m (converted to OSGM15, Trimble GeoXH 6000) (average of three surveys)

Summit Grid Reference:  SH 62418 55182 (Trimble GeoXH 6000)

Bwlch Height:  857.2m (LIDAR)

Bwlch Grid Reference:  SH 62168 55116 (LIDAR)

Drop:  66.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  7.23% (Trimble GeoXH 6000 summit and LIDAR bwlch)  

 

 

Pt. 914.6m

Summit Height:  914.6m (converted to OSGM15)

Summit Grid Reference:  SH 62309 55153

Bwlch Height:  904.1m (converted to OSGM15)

Bwlch Grid Reference:  SH 62336 55149

Drop:  10.6m

Dominance:  1.16%

 

 

Pt. 901.8m

Summit Height:  901.8m (converted to OSGM15)

Summit Grid Reference:  SH 62258 55130

Bwlch Height:  892.5m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 62268 55133 (LIDAR)

Drop:  9.3m

Dominance:  1.03%

 

 

Pt. 906.2m

Summit Height:  906.2m (converted to OSGM15)

Summit Grid Reference:  SH 61983 55146

Bwlch Height:  896.1m (converted to OSGM15)

Bwlch Grid Reference:  SH 61885 55154

Drop:  10.1m (Welsh Highland Sub Reinstatement)

Dominance:  1.11%

 

 

Pt. 563.0m

Summit Height:  563.0m (converted to OSGM15)

Summit Grid Reference:  SH 63821 55162

Bwlch Height:  552.8m (converted to OSGM15)

Bwlch Grid Reference:  SH 63750 55175

Drop:  10.2m (Welsh Highland Sub addition)

Dominance:  1.82%

 

 

Carreg Gwalch

Summit Height:  546.0m (converted to OSGM15)

Summit Grid Reference:  SH 64238 55249

Bwlch Height:  531.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 64229 55166

Drop:  14.7m (Welsh Highland Sub addition)  

Dominance:  2.70%

 

 

For further details please consult the Trimble Survey Spreadsheet

Friday, 10 June 2022

Mapping Mountains – Trimble Surveys – Arenig Fach


18.04.22  Chwarel Graig Ddu (SH 725 455), Pt. 658.45m (SH 727 458), Pt. 643.1m (SH 727 460), Pt. 535.0m (SH 723 461), Pt. 516.9m (SH 724 465) and Pt. 519.2m (SH 721 463)

Chwarel Graig Ddu (SH 725 455)

A tremendous amount of activity has been directed toward the discovery and confirmation of hills for Welsh 2,000ft (609.6m) P15 status.  This can be traced back to the 1920s when Arthur St George Walsh first compiled his list to these hills.  Not surprisingly Arthur worked purely in imperial measurement with a 2,000ft minimum height and a 50ft minimum drop criteria, although we do not know his exact methods, we do know that he was meticulous in his cataloguing of hills for this list.

In the late 1980s John and Anne Nuttall compiled their guide to Welsh hills using this same criteria.  Importantly they developed a surveying method that enabled many marginal hills to be either included or set to one side.  Their list was later augmented with survey results produced by Dewi Jones and soon afterward by me.  During this time I compiled a Welsh list using 500m minimum height and 15m minimum drop, which under the co-authorship of Aled Williams has since evolved into The Welsh Highlands list.  A sub-set within this list is the higher tier above 609.6m in height.  This higher tier is not a duplication of John and Anne’s work, or earlier lists such as Walsh’s for that matter.  Ever since its first compilation it has included hills not in the Nuttall’s list; for example, Castell y Gwynt and Fronllwyd, and it has also excluded hills listed by the Nuttalls; for example, Carnedd y Ddelw and Pt. 637.1m.

The surveying activity for these criteria was significantly expanded by John Barnard, Graham Jackson and myself who concentrated on the marginal hills produced by my previous surveys.  Using a level and staff and Leica GNSS equipment dramatically increased the accuracy of the results.  This has now been expanded by the use of the Trimble GeoXH 6000 and the availability of LIDAR.  By now it seemed all possible hills that stood any chance of inclusion to this height and drop category had been surveyed.  But this premise was wrong.  One last hill lurked in the background awaiting discovery!

The potential of the hill in question was first spotted by Aled Williams whilst scrutinising online 5m map contouring.  This was approximately two years ago and this hill had been on our radar ever since as this map has an uppermost 610m contour and bwlch contours between 590m – 595m.  However, as this hill is a part of a working quarry our intention was to inspect it from adjacent hillsides and hopefully confirm its validity. 

The map giving 5m contours 

The hill in question is positioned above Blaenau Ffestiniog in the heartland of Welsh slate mining and not surprisingly it has been terra-formed due to quarrying activity.  Hills created by man-made influence are shunned by some people, but there are many similar hills throughout Wales that are now included in a variety of hill list categories.

We endeavour to use best available data on any given day for our Welsh Highlands list.  By doing so we believe it enables our list to be as up-to-date as possible, even if a hill may be included one day and then excluded a month later due to continued terra-forming removing it from qualifying existence.  The main qualifying factor outside of the relevant numerical criteria is that the hill is considered solid and stable.  A good test for this is to jump up and down on its summit, if it does not move then it passes the test.  However, in this case we could inspect from a distance.

We met at 7.00am in the Cae Clyd car park at Manod on the outskirts of Blaenau Ffestiniog.  The forecast was for sunny conditions with the possibility of a rogue shower materialising in the afternoon.  At this time in the morning we could have been excused for not believing this, as the cloud base was low obstructing all near hills. 

An old gate leading us on the footpath toward the hill

The cloud at least kept the temperature pleasant as we made our way to the end of the paved road and then continued on a track toward a public footpath.  This was the first time I had approached these hills from this direction and as we gained height the cloud rose with us, it seemed our timing was perfect. 

Misty early morning

Our route took us to Llyn y Manod.  In years gone by there was a fishing hut beside this lake, any vestige of this or its remains were out of view today as the mist still skimmed the land beside the lake as we approached. 

Llyn y Manod with Manod Bach rising above

From the lake an old quarry track leads up the western slopes of Manod Mawr which loomed above us as a great bulk of a hill.  This track meets the disused incline leading from the quarry down toward Blaenau Ffestiniog.  From here it was only a short walk to where the main quarry road emerged out of the still rising mist. 

Nearing the quarry road

At the intersection of the quarry road leading up toward the high point of our potential new hill the public footpath diverts around to its south and east.  This then climbs to meet the easterly slopes of the adjacent 658m map heighted hill.  From here we looked down on our potential new hill which has a quarry road passing over its summit area.  Because of this we knew that it was solid and stable. 

The intersection between the quarry road and the public footpath

On the summit of the 658m map heighted hill we met the only other person we saw on the hill all day.  He told us he had Covid and advised we keep our distance, when doing so I was standing downwind of him; I soon changed my position and thanked him for telling me so. 

Looking down on Chwarel Graig Ddu

We then Abneyed the summit of this hill and decided to gather data from the highest ground visible at the base of the large summit cairn.  The view from this summit is extensive and as my last visit to this hill was in March 2004 it was good to be back after a gap of 18 years. 

Approaching the high point of the day

To our west we watched as darkened cloud edged its way northward toward the high Glyderau and Carneddau.  It was now early afternoon and the cloud was thickening and even though threatening darkened cloud occasionally built up over the tops we visited, it remained dry, which for our purposes on the hill was welcome. 

Gathering data at the summit of Pt. 658.45m (SH 727 458)

We now had four potential sub hills to survey, the first of which was only a short distance below us.  I had surveyed this first small prominence hill with a basic levelling staff in August 1998 and the other three in October 2005, and Aled had compared my results to his interpolation of the 5m contouring available online.  With the aid of the Trimble GeoXH 6000 we could now put accurate heights and positions to each of these four hills.

One of the joys of surveying is the places such a pastime takes you to, and these potential sub hills did just that, as the land hereabouts is probably seldom visited.  But today it was quiet with light and shade across the landscape adding depth to perspective, with each hill in turn giving extensive and rewarding views.

After surveying the first potential sub we followed the line of a fence down steep ground to where a complicated series of summits and bylchau are placed.  Our three remaining hills where positioned relatively close to each other and therefore surveys came thick and fast. 

Gathering data at the summit of the third of four potential sub hills

Moel Penamnen

The summit of our penultimate hill gave views across Llyn Bowydd and Llyn Newydd to the shapely profile of Moel Penamnen.  This was our furthest northerly point during the day; from here we headed south surveying another potential sub on our way. 

Looking out toward Cnicht

Beside Llyn y Manod

From the summit of our last potential sub hill all that remained was the walk out aiming for the eastern shore of Llyn Du Bach, which connected us with a path leading toward the incline heading down from the higher tops toward the outskirts of Blaenau Ffestiniog.  We crossed this and made steady progress up to the earthen track leading to Llyn y Manod.  As we gained the track we rested, which for me was a welcome break. 

Late afternoon light

Manod Bach

Our remaining route followed the path on the eastern shore of the lake before joining our inward route from earlier in the day.  The atmospheric misted scene from early morning had long been replaced by blue skies, late afternoon warmth, extensive views and the knowledge that the main aim of the day had been completed.


Postscript

Since surveying these hills full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for these hills have been analysed using this technique, and where appropriate these results appear below. 

 

Survey Result: 

 

Chwarel Graig Ddu

Summit Height:  613.3m (LIDAR)

Summit Grid Reference:  SH 72504 45533 (LIDAR)

Bwlch Height:  592.2m (LIDAR)

Bwlch Grid Reference:  SH 72456 45744 (LIDAR)

Drop:  21.1m (LIDAR) (Uchaf addition) (600m Sub-Twmpau addition)

Dominance:  3.44% (LIDAR)

 

 

Pt. 658.45m

Summit Height:  658.45m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 72741 45844 (Trimble GeoXH 6000)

Bwlch Height:  593.9m (LIDAR)

Bwlch Grid Reference:  SH 72903 45460 (LIDAR)

Drop:  64.6m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  9.81% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

Pt. 643.1m

Summit Height:  643.1m (converted to OSGM15)

Summit Grid Reference:  SH 72780 46053

Bwlch Height:  633.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 72816 46026

Drop:  10.1m

Dominance:  1.57%

 

 

Pt. 535.0m

Summit Height:  535.0m (converted to OSGM15)

Summit Grid Reference:  SH 72348 46195

Bwlch Height:  524.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 72392 46231

Drop:  10.8m

Dominance:  2.01%

 

 

Pt. 516.9m

Summit Height:  516.9m (converted to OSGM15)

Summit Grid Reference:  SH 72414 46598

Bwlch Height:  507.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 72346 46467

Drop:  9.9m

Dominance:  1.92%

 

 

Pt. 519.2m

Summit Height:  519.2m (converted to OSGM15)

Summit Grid Reference:  SH 72188 46369

Bwlch Height:  509.6m (converted to OSGM15)

Bwlch Grid Reference:  SH 72312 46434

Drop:  9.6m

Dominance:  1.85%

 

 

For further details please consult the Trimble Survey Spreadsheet

  

Thursday, 7 October 2021

Mapping Mountains – Trimble Surveys – Y Llethr

 

24.08.21  Rhinog Fawr (SH 656 290, only bwlch surveyed), 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:  720.9m (LIDAR)

Summit Grid Reference:  SH 65696 29009 (LIDAR) 

Bwlch Height:  352.6m (Trimble GeoXH 6000)

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

Drop:  368.2m (LIDAR summit and Trimble GeoXH 6000 bwlch)

Dominance:  51.08% (LIDAR 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