04.06.15 Crib y Rhiw
(SH 663 248), Diffwys (SH 661 234) and Pt. 643.2m (SH 648 229)
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| Diffwys (SH 661 234) |
Out today with John and
Graham with the southern Rhinogydd planned as our destination. Our main aim for the day’s surveying was
Diffwys which is listed by Alan Dawson as a Submarilyn with 148m of drop, as
150m is the qualifying mark for Marilyn status; this hill had been on our
prioritised list of hills to survey for a number of years.
We met in Bala and took
one car down to Bont-ddu and turned right toward the hills on a narrow road
that gained height and parked at its end at SH 656 201, where three cars can
easily be left.
The weather was blissful
with clear blue skies and good clarity of colour, however it was warm which no
doubt would make us suffer on the up hills.
The last time I had spoken to one of the local farmers in this area he
had told me that the path that leads up the Braich had been churned up by trail
bikes and in places it now resembled a stream.
It is only a matter of a few metres to the gate that leads onto this
path from where the car had been parked and confronting us as we approached the
gate was a police sign warning everyone to ‘slow down’. I wondered if this was an act of humour or
perhaps a sign put there to try and discourage the trail bikes.
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| The sign at the start of the path |
I set off before John
and Graham and tried my utmost to set a reasonable pace up the path as it
gained steady height onto the open hillside of the ridge leading upto the hill
that the Nuttalls list as Diffwys West Top.
But my pace was slow, partly because of the heat but also the weight I
was carrying, as a camera, video camera and the Trimble weight 10lb, added to
this was a large tripod and a 75 litre capacity rucksack to strap the tripod
onto, within the rucksack were the usual things required for a day in the
hills, all of this adds weight, and added weight means a slower pace.
Even though I puffed on
the uphill the views compensated as Diffwys looked resplendent with its
southern arm stretching out over Craig Aderyn, the hill was bathed in morning
sunshine with the shadowed cloud movement giving depth to the landscape.
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| The shapely profile of Diffwys |
Soon John and Graham
approached and slowly overtook me as we all headed up the Braich and once at
its top we crested the western ridge of Diffwys and swung right following a
good path beside a dilapidated wall and a double fence. We now had a decision to make as we could
either survey this western top and then continue to the summit and then the
bwlch of Diffwys and descend on a green track beside the Afon Cwm-llechen, or
we could traverse the western bulk of Diffwys and survey its bwlch first and
use our inward route as our descent and survey this western top later in the
afternoon, we decided upon the latter option.
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Graham and John just about to catch and overtake me
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The continuation of the southern Rhinogydd down to the Afon Mawddach and the sea
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| Continuing over the hill that the Nuttall's name as Diffwys West Top |
By now it had really
warmed up and all I wanted to do was stop and take the weight off my
shoulders. The traverse of Diffwys was
new to me; I had never done this before and found the prospect of venturing
onto new ground to be partly stimulating in my ever increasing state of
weariness. We initially followed a sheep
track as it contoured its way around the hillside; this seemed to disappear as
we approached a section of wet ground, this traverse was proving fun as it gave
a marvellous viewpoint across Llyn Bodlyn to the rounded bulk of Moelfre with
the elongated arm of north-west Wales stretching out to Ynys Enlli beyond.
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Traversing the western flank of Diffwys
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The rounded profile of Moelfre with Llyn Bodlyn in the foreground
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| Heading toward the bwlch of Diffwys |
This route also gave a
different viewpoint toward Y Llethr and Crib y Rhiw with Llyn Dulyn nestled
under the crags of the latter hill.
Occasionally I would catch upto John and Graham as they waited for me;
we had now rounded the western shoulder of Diffwys and could see its bwlch
ahead of us. Between it and us was
varied ground with copious amounts of bilberry, rock and a number of small
ridges to clamber over and around. Progress
was being made and soon we were walking on the flatland beside small pools just
on the western side of the hill’s bwlch.
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Y Llethr and Crib y Rhiw with Llyn Dulyn in the foreground
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Typical Rhinogydd ground of rock, lake and dramatic views
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The critical bwlch of Diffwys is the right hand notch of the two on the left of the photo
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| Crib y Rhiw from near to its connecting bwlch with Diffwys |
Once over the ridge wall
that strides between these hills we arrived at the bwlch, and the level was set
up with John taking readings to the staff that Graham was holding, I tried to
recover and stood on an intervening small ridge taking photos down onto
proceedings. The bwlch had two options
for its critical point, the one nearest Diffwys proved to be the lower and soon
the Leica GS15 was set up and gathering data.
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Using the level and staff to survey for bwlch position
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| The Leica GS15 set-up at the critical bwlch of Diffwys |
To our south Diffwys
looked proudly grand with the wall robustly stretching toward its summit, in
the opposite direction lay Crib y Rhiw with its rocky grassed flank looking
eloquent in shape and appealing to the eye.
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Diffwys from its critical bwlch
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| The connecting solid wall stretching upto Crib y Rhiw |
We took a measurement
offset between the critical bwlch and that of an elevated rock outcrop and
gathered five minutes of Trimble data to compare results against that of the
Leica GS15.
I now wanted to visit
the summit of Crib y Rhiw and keep my totals for these three Nuttalls on par
with one another. I also wanted to
gather data from its summit as to my knowledge no spot height has ever appeared
on any map for the high point of this hill.
As I wearily plodded up the path that leads to its summit Graham
remained at the bwlch with the equipment and John set off behind me and soon
passed me.
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| Y Llethr from the summit of Crib y Rhiw |
The high point of Crib y
Rhiw is at the southern end of its summit ridge, once I stumbled my way upto it
I placed the Trimble on a small embedded rock at the summit and gathered five
minutes of data. During this John headed
north to examine another high point and once there looked back to where I was,
we both concluded that the high point of the hill was at the southerly end of
its ridge.
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| Gathering data with the Trimble at the summit of Crib y Rhiw |
By the time we arrived
back at the bwlch the hour data collection for the Leica Gs15 was almost
complete, we just had time for John to do a couple of minutes to the video
camera before the equipment was switched off and packed away. The next uphill proved utterly debilitating
as it was so warm and without any form of breeze.
The uphill from the bwlch
to the summit of Diffwys was a slow, hot grind.
I stopped on many occasions and tried to recover my breath as I took
photos back toward Y Llethr and Crib y Rhiw and over toward the shapely profile
of Moelfre. Slowly progress was made,
but it was at a cost as the sun was taking its toll. I have experienced the sun’s debilitating
effect when out in the hills on a number of occasions and can feel its piecing,
unrelenting strength that saps all forms of energy, I also know that to make
progress I have to take it very steady and just aim ahead to a set point and
when reached to take a rest, and then repeat this until the summit is reached.
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Crib y Rhiw from the ascent of Diffwys
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| Moelfre from the ascent of Diffwys |
The last few hundred
metres to the summit of Diffwys was a wobbly affair, as although the path was
good and the ridge was relatively flat I still had to rest and gasp for
air. Eventually I reached the trig
point, got the rucksack and camera and Trimble off my shoulders, unstrapped the
tripod and then flaked out on the ground.
During this John and Graham were taking readings on either side of the
ridge wall and pinpointing the high point of the hill to be about five metres
to the north of the trig point. All I
could do was groan on the ground and occasionally stumble to my feet and take a
photograph.
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The weary, hot plod up Diffwys
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John using the mini tripod and level to take readings from the top of the wall at the summit of Diffwys
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| Taking readings on the eastern side of the wall at the summit of Diffwys |
We took data with the
Leica GS15 at the high point and another five minutes of Trimble data to the
top of the trig, having taken a measurement offset between the summit and the
trig. Ahhhhhh, time to rest, eat, take
on water and try and recover.
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The Leica GS15 set up at the summit of Diffwys
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The Trimble gathering data at the top of the trig pillar on Diffwys
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Once an hour of data had
been collected the Leica GS15 was packed away and we headed down to the
connecting bwlch with the hill that the Nuttalls list as Diffwys West Top. I proceeded to gather data with the Trimble from the area of the bwlch and then joined John and Graham at the hill’s summit.
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| Gathering data at the bwlch area of the hill that the Nuttall's list as Diffwys West Top |
By the time I arrived at
the summit John was taking readings with the level and Graham had the staff in
hand and had positioned a row of flags across the plateaued summit area. A few minutes later and we had pinpointed the
high point to be 4 metres from where a small cairn has appeared over recent
years. We moved the cairn to the high
point and took a data set with the Trimble.
All that remained was to descend back to the awaiting car.
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Using the level and staff to ascertain the high point of Pt. 643.2m
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| Gathering data from the top of the small cairn |
The descent proved
rather beautiful as early evening light had broken through the western high
cloud that had pushed in over the last hour of the walk. This gave a delicate feel to the landscape
and highlighted the hills in a diffused and welcome light.
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On our way down
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| Delicate evening light on Diffwys |
As I passed the old
marker stone close to the end of the path I stopped and took a few photographs
and looked back toward Diffwys as it stood grandly on display, ahead of me over
the Afon Mawddach lay Cadair Idris with the evening light striking and
highlighting its northerly cirque of cliffs.
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The old marker stone
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| Cadair Idris bathed in evening light |
These mountains are
special in their beauty; they are testaments to the ravages of the past when
glaciers once carved out the land and left sculptured ridges and high cymoedd
which are now inherent in the landscape.
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
LIDAR has been used in preference to that produced by the Trimble.
Survey Result:
Crib y Rhiw
Summit Grid Reference: SH 66368 24868
Bwlch Height: 652.1m (converted to OSGM15) (from subsequent Trimble GeoXH 6000 survey)
Bwlch Grid Reference: SH 66080 25302 (from subsequent Trimble GeoXH 6000 survey)
Drop: 29.2m
Dominance: 4.28%
Diffwys
Summit Height: 750.4m (converted to OSGM15, Trimble GeoXH 6000) 750.4m (converted to OSGM15, Leica GS15)
Summit Grid Reference: SH 66127 23413
Bwlch Height: 602.9m (converted to OSGM15, Trimble GeoXH 6000) 602.8m (converted to OSGM15, Leica GS15)
Bwlch Grid Reference: SH 66613 24396
Drop: 147.5m (Trimble GeoXH 6000) 147.6m (Leica GS15)
Dominance: 19.67%
Pt. 643.2m
Summit Height: 643.2m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SH 64821 22928 (Trimble GeoXH 6000)
Bwlch Height: 621.2m (LIDAR)
Bwlch Grid Reference: SH 65177 23005 (LIDAR)
Drop: 22.0m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Dominance: 3.42% (Trimble GeoXH 6000 summit and LIDAR bwlch)
For further details please
consult the Trimble survey spreadsheet click {here}
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