Sunday, 22 April 2018

Mapping Mountains – Trimble Surveys – Moelwynion

11.03.18  Pt. 561.6m (SH 717 549), Moel Siabod (SH 705 546), Pt. 815.9m (SH 708 550), Pt. 811.2m (SH 709 551) and Pt. 800.8m (SH 711 552)

Pt. 561.6m (SH 717 549)

For many years it seemed as if I was walking with blinkers on, being preoccupied with the 2,000ft mountains of Wales with little regard for visiting lower heighted hills.  Nowadays I get pleasure enough on the lower P30s, but when opportunity arises to visit the higher hills their dramatic architecture is savoured, and today was such an occasion as along with Mark and Aled we planned on visiting Moel Siabod and a number of lower satellite peaks whose existing and potential P15 status needed clarifying.

Moel Siabod is a wonderful hill set apart from its higher neighbours, its 872m map heighted summit commands extensive views and is a relative recent addition to Mark’s P600 Majors list, only entering this list as the 272m bwlch spot height that appears on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website gives the hill 600m of map spot heighted drop.

Having left three cars at different points for optional descent routes we ascended via Pont Cyfyng, walking up the narrow lane to the footpath gaining the track leading to the north-eastern ridge of Moel Siabod, across the valley spring sunshine picked out the rugged profile of Creigiau Gleision and the pyramidal shape of Pen Llithrig y Wrach.  However, the sunshine was not to last as high greying cloud would slowly ebb in from the south adding wisps to the higher tops with the prospect of incoming rain.

Creigiau Gleision

Pen Llithrig y Wrach

The first hill we wanted to investigate is listed as an Uchaf, these are the Welsh P15 hills at and over 500m in height, and the hill only entered this list through a basic levelling survey conducted in July 2004.  Following a path toward a quarry lake the hill rose above slightly rounded and elongated in profile it sits away from its much higher neighbour and is probably seldom visited and yet it is situated in a marvellously wild landscape of heather moor, bog and rock.

Moel Siabod looked dramatically appetising as we descended to the hill’s connecting bwlch which has a number of small attractive pools situated on it, we judged where the critical bwlch lay and as I set the Trimble up and floundered in the overly wet bog adjacent to the larger of these pools, Mark and Aled headed off to investigate if there was an outflow from the opposing side of the pool.

Descending to the connecting bwlch of Pt. 561.6m (SH 717 549)

Mark with Moel Siabod as backdrop

Gathering data at the critical bwlch of Pt. 561.6m

This hill has two tops and both were Trimbled, with each summit consisting of a large rock.  As the more north-westerly top was Trimbled Mark and Aled visited the south-easterly one, I looked out as they waited on this summit with the cliff face of Moel Siabod as backdrop rising skyward dwarfing our position.

Gathering data from what proved to be the lower of the two tops

Aled and Mark on the south-westerly top of Pt. 561.6m

Gathering data from the summit of Pt. 561.6m

Leaving the hill we followed a narrow path across the outflow from Llyn y Foel and joined the lower part of Daear Ddu, which if wanting a scramble is the way to approach Moel Siabod.  Daear Ddu is the eastern ridge of Moel Siabod and I’ve enjoyed its rock on many occasions, the first being with a horrendous hangover when I was sick on the hill, not a pretty sight!

Beside Llyn y Foel

As height was gained the view opened, down upon Llyn y Foel and across the Eryri peaks to the far off Berwyn and Bryniau Clwyd.  The ridge was fun, as it ever is, with just enough hand on rock to bring a sustainable amount of enjoyment.

Llyn y Foel

The north-eastern ridge of Moel Siabod with the three tops which were later surveyed

By the time we crested the summit ridge cloud had built and as the Trimble clung aligned to the highest rock gathering its all-important data, mist quickly rolled in and would remain with us until we descended.

The north-eastern ridge from close to the summit of Moel Siabod

The view south-west just before the mist rolled in

Gathering data at the summit of Moel Siabod

If time permitted we hoped to survey at least two of the three tops on the upper part of the north-easterly ridge of Moel Siabod, each is a jumble of rock with two of the three bylchau being tight with plunging drops nearby down horrendously steep gulleys.

After the Trimble had gathered its allotted data from the summit of Moel Siabod I joined Mark and Aled in the large wind shelter just below the high point for a bite to eat before continuing to the three rocky tops. 

As we walked through the mist toward the first connecting bwlch we discussed the merits of what ones to survey as dusk would be approaching on our descent and as the weather had closed in it looked as if the forecast rain would overtake us, these weren’t ideal conditions to survey castellated summits above mighty drops.  The impending problem was solved when Aled suggested a two minute data set at each bwlch and summit, this is the minimum suggested for data collection by Trimble.  This would enable the three tops to be surveyed in turn and would complete all tops adjoined to Moel Siabod then having been Trimbled.

The ridge proved fun as the rock was damp with rock step after rock step negotiated from one summit to bwlch and onward to the next summit.  These surveys came thick and fast with barely a moment to contemplate some of the Trimble bwlch positions with two being on the edge of mountainous drops down steep gulleys.

A precarious position for a Trimble

As the last summit was Trimbled Mark headed down to a fence which gave access to the path leading to where one of our cars was parked beside Plas y Brenin and Llynnau Mymbyr, Aled and I soon followed.

Gathering data  from the summit of Pt. 800.8m

It had been a good day on the hill with ten surveys completed, with an enjoyable time picking out an occasional scramble whilst visiting the summit of one of Eryri’s special mountains.  We ended the day in the Bryn Tyrch at Capel Curig with good conversation and a welcome meal.


Survey Result:

Pt. 561.6m

Summit Height:  561.6m (converted to OSGM15)

Summit Grid Reference:  SH 71781 54962

Bwlch Height:  546.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 71805 55107

Drop:  15.3m (Uchaf status confirmed)

Dominance:  2.72%

Moel Siabod

Summit Height:  872.2m (converted to OSGM15)

Summit Grid Reference:  SH 70524 54631

Bwlch Height:  272.3m (converted to OSGM15) (previously Trimbled)

Bwlch Grid Reference:  SH 66044 55603 (previously Trimbled)

Drop:  599.9m (Trimble summit and Trimble bwlch) 599.7m (Trimble summit and LIDAR bwlch) (P600 Major deletion confirmed)

Dominance:  68.78%

Pt. 815.9m

Summit Height:  815.9m (converted to OSGM15)

Summit Grid Reference:  SH 70859 55036

Bwlch Height:  808.9m (converted to OSGM15)

Bwlch Grid Reference:  SH 70797 54991

Drop:  7.0m (non Uchaf status confirmed)

Dominance:  0.86%

Pt. 811.2m

Summit Height:  811.2m (converted to OSGM15)

Summit Grid Reference:  SH 70955 55120

Bwlch Height:  803.9m (converted to OSGM15)

Bwlch Grid Reference:  SH 70898 55084

Drop:  7.3m (non Uchaf status confirmed)

Dominance:  0.90%

Pt. 800.8m

Summit Height:  800.8m (converted to OSGM15)

Summit Grid Reference:  SH 71115 55231

Bwlch Height:  787.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 71076 55224

Drop:  13.3m (non Uchaf status confirmed)

Dominance:  1.66%

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