06.10.18 & 10.10.18 Foel Gron (SH 583 621) and Pen y Bigil (SH
576 621)
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| Pen y Bigil (SH 576 621) |
These two hills overlook
Llyn Padarn and the Yr Wyddfa range and form a part of the western extension of
Elidir Fawr as it descends to the lowlands of the Glyderau. I’d visited the lower part of Pen y Bigil
many years ago when along with my brother we investigated numerous rock
outcrops for scrambling possibilities; otherwise the two hills had stared back
at me for many years rising in their bouldered confines above the small
community of Deiniolen.
I approached from the
south walking up a public footpath enclosed by a stone wall and wired fence on
one side and upright slate sides on the other.
The footpath crested the southern ridge of Foel Gron and it was here
that I headed on to the hill as a faint path is marked on Ordnance Survey maps
and I hoped this would lead me toward the summit bi-passing the profusion of
stone walls that mark this hill.
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| The way to the hill |
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| Yr Wyddfa dominating the southern view |
My hope for an easy ascent
was dashed as a stone wall soon barred further progress, a cumbersome climb
then followed. Once on the other side
the summit was within reach.
By now the sun had made
an appearance, a welcome addition as the skies in the main had remained grey over
the last few days. The play of light
interspersed with shadow gave perspective to the land with Yr Wyddfa dominating
the southern view.
I took two data sets
from the summit area of Foel Gron, the first on a small grassed knoll beside a
stone wall where the 353m spot height appears on the map. This entailed wedging my rucksack on top of
the wall and with the Trimble perched on my rucksack it now cleared the barb
wired fence which also adorned the stone wall.
Once the offset between its internal antenna and the ground below was measured
I stood back as it gathered its allotted data and looked out toward the high
peaks of Eryri.
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| The first data set on Foel Gron |
The second data set was taken
from ground to the south of the grassy knoll, this is where 2m DTM LIDAR gives
the summit to be positioned, and visually this looked higher than the grassy
knoll, although eyesight alone is not ideal for such interpolation. I also noted ground further to the west that
looked of similar height, which I later visited but did not take a third data
set from.
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| The second data set on Foel Gron |
Once data were stored I
packed the Trimble away and headed down toward the minor road between the two
hills. I found the descent relatively
easy and used gaps in a number of walls to gain access to the road.
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| Descending Foel Gron toward Pen y Bigil |
It was only a short
distance from where I emerged on the road to the access track that leads up to
the high mast beside the summit of Pen y Bigil.
On my way up the track I chatted to a woman in her car who had retired
and found the house of her dreams, this looked out on Yr Wyddfa and nestled in
to the side of Pen y Bigil, she said that it was a beautiful view, although it
was prone to get a bit of weather!
The summit of Pen y Bigil
is beyond the mast and comprises a rock outcrop, once the Trimble was balanced
aligned with the high point I sat below it and looked down on Llyn Padarn and
over its glistening waters to the pointed top of Yr Wyddfa, a stunning place to
be in the early afternoon.
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| Gathering data at the summit of Pen y Bigil |
Once data were stored I
retraced my inward route down the track and took a data set from where LIDAR
implies the natural bwlch of Pen y Bigil to be situated. Just below this position the minor road has
carved through this part of the hill forming a cutting with the road bwlch now
lower on the hill to hill traverse. The
remaining natural bwlch was beside the track which is slightly elevated above
the grazing fields on either side.
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| Yr Wyddfa from Pen y Bigil |
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| Gathering data at the remaining natural bwlch of Pen y Bigil |
After the fourth data
set of the walk it was only a short walk on the minor road back to my car, and
just one small hill remained to visit and Trimble before visiting my brother in
Ysbyty Gwynedd, and that hill was Dinas Dinorwig (SH 549 652).
Postscript:
I later checked the
details for Foel Gron with the 1m DTM LIDAR model and discovered that land to
the west of where I took the second summit data set from is given as
higher. I thought drat, or other such
thoughts!
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| Foel Gron (SH 583 621) |
I could easily forgo
such things as 1m DTM LIDAR only gives this westerly point as being a few
millimetres higher than where I took the second summit data set from, but this
niggled in the back of my mind, and therefore I knew I needed to re-visit and
complete the task.
The opportunity to do so
came four days after my initial visit, as I’d been out visiting and surveying a
number of P30s in the north-eastern Carneddau and Foel Gron was only a short
diversion from my route back toward Nantlle.
Although the forecast
for the day predicted high winds, the north-eastern Carneddau had been well
sheltered with only a semblance of light breeze during the many hours that I’d
been wandering the hills earlier in the day, but upon arrival at the base of
Foel Gron the wind whipped the land in a frenzy compared to the preceding hours
of tranquillity.
I was soon at the top of
Foel Gron having ascended direct from the road between it and Pen y Bigil, this
was my descent route on my first visit and proved an easy way off the hill.
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| Yr Wyddfa from Foel Gron |
The Trimble directed me
to the 1m DTM LIDAR summit which comprises ground I had looked out on and later
visited after the two summit surveys of this hill previously conducted.
Once at this summit I
remodelled a small cairn to wedge the Trimble in place and safeguard it from
the strong wind and measured a 0.13m offset between its internal antenna and
the ground at its base and set it to gather data.
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| Gathering data at the summit of Foel Gron |
As it did its stuff I
stood below it facing in to the wind and watched as the sun cast wonderful
colour on the hill, looking up the valley Yr Wyddfa dominated the view, a great
greened bulk with shadowed plunging cliff rimmed sides; a marvellous sight.
I let the Trimble gather
15 minutes of data as I was in no rush and stood happily as the wind span
across the hill. On occasion it feels
the most natural thing to stand and face elemental forces whilst they are at
play, and today it was a delight as the wind and its ferocity and uncontrolled noise
hurtled past, this is especially so on a moorland hill as if blown over it
would give a relatively soft landing on heather.
I wanted to stay on this
hill until the sun sank in the western sea, but the colour enriched hillsides
drew me down, and once data were stored and the Trimble packed away I slowly
made my way back down the hill.
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| Old and new in Deiniolen |
As I drove the short
distance to where the road widened beside a church I stopped to change out of
my boots and hill walking gear, and spent a number of minutes watching the
oranged glow as the sun forever sank deeper in the sky.
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| Sunset from Deiniolen |
It had been a day of
contrasts starting with delicate mist as it played on the banks of Llyn
Gwynant, followed by the silent flight of a barn owl, discovering a cannabis
plant on a hill, meeting a farmer and being invited in for a refreshing drink
and shortbread, meeting the Gorse Hill Caravan Park owner, having a number of
hill names confirmed, my legs ripped by copious amounts of gorse and now
watching the sun slowly set. A wonderful
way to spend a day.
Survey Result:
Foel Gron
Summit Height: 351.6m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SH 58359 62170 (Trimble GeoXH 6000) (summit relocation confirmed)
Bwlch Height: 319.3m (LIDAR)
Bwlch Grid Reference: SH 58675 62194 (LIDAR)
Drop: 32.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Dominance: 9.19% (Trimble GeoXH 6000 summit and LIDAR bwlch)
Pen y Bigil
Summit Height: 331.0m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)
Summit Grid Reference: SH 57600 62119 (Trimble GeoXH 6000)
Bwlch Height: 292.6m (LIDAR)
Bwlch Grid Reference: SH 58014 62043 (LIDAR)
Drop: 38.4m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Sub-Trichant reclassified to Trichant)
Dominance: 11.59% (Trimble GeoXH 6000 summit and LIDAR bwlch)
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