30.06.18 Waun Rydd (SO 062 206 [only bwlch surveyed SO
031 205]), Fan y Big (SO 036 206), Gwaun Cerrig Llwydion (SO 041 196) and Craig
Gwrelyg (SO 055 203)
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| Gwaun Cerrig Llwydion (SO 041 196) |
With the weather set
fine I was spurned in to surveying action and headed south to the sublime peaks
of Bannau Brycheiniog. Although I had
three hills and another’s bwlch planned to survey it was Fan y Big above all
others that drew my attention. This hill
is currently listed as a Simm and Hewitt, with 600m and 2,000ft their
respective qualifying heights and 30m their minimum drop, with both lists
authored by Alan Dawson.
Fan y Big is positioned
on the main Bannau Brycheiniog ridge and is situated east of Cribyn and to the
west of Waun Rydd, with both of these hills being higher, however Fan y Big has
an appealing summit with great sweeping drops in to Cwm Cynwyn and Cwm Oergwm
and a narrowing grassy north ridge that leads direct to its summit.
Its current status as
both a Simm and Hewitt is border line as it is listed with 30m of drop, which
is the minimum required for these classifications, with this drop value based
on the 719m summit spot height on the Ordnance Survey 1:50,000 Landranger and
1:25,000 Explorer map and the 689m bwlch spot height on the Ordnance Survey
Interactive Coverage Map hosted on the Geograph website.
Although this hill has
always been a marginal P30, to my knowledge it was John Kirk who first petitioned
for this hill to be accurately surveyed as he doubted its P30 status, his
doubts seemed to have been proven correct when I asked Aled to analysis this
hill with LIDAR, resulting in a 28.2m drop, which is insufficient for both Simm
and Hewitt status, Alan was notified of Aled’s LIDAR analysis and hoped to
visit the hill and survey it with his Leica RX1250 later in the year, this was
in 2017, but the opportunity to do so did not arise.
I then reclassified this
hill to a 700m Sub-Twmpau based on the result produced by Aled’s LIDAR analysis
and waited for Alan to venture south on one of his Welsh surveying bonanzas. No more was heard about Fan y Big until Tony
Jenkins posted on the Tump forum a link to my 700m Twmpau Hill Reclassification
post on Mapping Mountains, and this stirred me in to action, but with the
weather predicted to be another warm day I needed to get an early start if I hoped
to survey this and adjacent hills before the hot conditions took their toll.
I set my alarm for
3.00am and was parked on the southern side of the Beacons and walking by
5.45am. The sky was clear blue and early
morning freshness pervaded the land which was accentuated by a light breeze,
bringing comfort to those of us who suffer when the hill going becomes
extremely warm.
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| Early morning start and the way to the hill |
Even at this early hour
there were people heading for the hill, and more appeared as I made good
progress up the contouring path beside the Taf Fechan Forest, which led on to
open hillside and gained height above the Upper Neuadd Reservoir. I had contemplated visiting Cribyn using a
path from its connecting bwlch with Fan y Big, but decided that this hill could
wait for another day.
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| Pen y Fan |
At just before 7.00am
the Trimble was positioned at this first bwlch which is the critical one for
Waun Rydd and data being gathered, all those I had seen on the path were now
heading for Cribyn and Pen y Fan and land around the bwlch was remarkably quiet
for the Beacons at a weekend. Just as
the last of the 360 datum points were collected a mountain biker appeared
pushing his bike up toward the bwlch, the Trimble was closed down, packed away
and I was heading up the steepening path toward the summit of Fan y Big before
he reached the top of the path leading to the bwlch.
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| Gathering data at the critical bwlch of Waun Rydd |
Fan y Big has a
marvellous vantage point with the higher Beacons to its west and the
continuation of the main ridge to its east, its high point is easily
identifiable and consists of a small grassed hummock beside the eroded path
that continues down its northern ridge.
As I set the Trimble up with its internal antenna aligned with the high
point of the hill the sky still shone blue but to the east Mynyddoedd Duon were
battling with early morning mist and a northerly mist bank quickly headed south
toward the hill.
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| The Trimble set-up position at the summit of Fan y Big |
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| Mist banks over Mynyddoedd Duon |
I decided that the
importance of the survey constituted two ten minute data sets from the summit
and also from the bwlch, and as the first summit survey neared completion the
mist rolled in up each cwm to the immediate east and west. I quickly closed the Trimble down and
reactivated it for its second ten minute data set, as it beeped away collecting
its individual data appoints I was treated to a beautiful scene as mist
enveloped the land below and the sun from behind created a Brocken spectre on
the mist below, it had been many years since I had last experienced such a
treat on a hill and I stood and stared and enjoyed and savoured for many a
minute as the mist forever changed and the sun disappeared to reappear again
and cast another Brocken spectre below.
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| Gathering data at the summit of Fan y Big |
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| Brocken spectre from the summit of Fan y Big |
By the time I closed the
Trimble down I felt content with my lot in the world and headed off following
the ridge toward the next important survey; the critical bwlch of Fan y
Big. This proved easy to identify even
without the ten figure grid reference produced by LIDAR analysis directing me
to its critical point. I again took two
ten minute data sets and sat sheltered from the increasing breeze which whipped
mist up from the cwm below across the ridge in delicate and fast moving
formations.
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| Gathering data at the critical bwlch of Fan y Big |
Two hills remained to be
surveyed, the first of which was Gwaun Cerrig Llwydion which only just misses
Uchaf status according to LIDAR analysis and a basic levelling survey I conducted
many a year ago. I left the bwlch of Fan
y Big and gained height in to the freshening mist and emerged on the summit as
the heat of the morning started to burn the mist away. The summit of this hill lay close to the
eroded path and another data set was gathered.
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| Gathering data at the summit of Gwaun Cerrig Llwydion |
The bwlch of Gwaun
Cerrig Llwydion is an utter contrast to that of Fan y Big and lies in a morass
of flatness with dry bog, tussock and a wildness to it, I was thankful that it was
free of mist and if not for the ten figure grid reference produced by LIDAR
which directed me to its critical point, I could easily have been 50 metres
away with my positioning for the Trimble based purely on my eye. As the Trimble gathered its allotted data I
sat on a rock and luxuriated myself in the morning sun, it was still only
9.15am and only two surveys remained.
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| Gathering data at the critical bwlch of Gwaun Cerrig Llwydion |
Leaving the bwlch I re-joined
the eroded ridge path as it sped along above the upper reaches of Cwm Oergwm
toward the final summit of the day which is the high point of Craig Gwrelyg,
which is listed as an Uchaf and Pellennig hill.
 |
| Gathering data at the summit of Craig Gwrelyg |
As the Trimble gathered
its last summit data set of the day a murky cloud bank remained to the west
hiding Fan y Big and its higher neighbours, and yet the part of the ridge I was
on was now bathed in sunshine which over the next 30 minutes gradually
increased in strength.
All that remained was
the bwlch survey for Craig Gwrelyg and again the ten figure grid reference
produced by LIDAR took me down to it.
Whilst waiting for the Trimble to achieve its 0.1m accuracy level before
data should be logged I chatted with a group of walkers who were out on a
navigation course and asked their opinion of where this critical bwlch lay, I
had conflicting opinions given me with one deciding it was placed firmly on the
upward part of the hill to hill traverse!
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| Gathering data at the critical bwlch of Craig Gwrelyg |
As I packed the Trimble
away the heat had increased, but all I now faced was downhill and although the
first beads of sweat were now on my brow, I set off on the path following the
escarpment edge above Blaen y Glyn with an added momentum, happy in the
knowledge that all planned surveys were complete and that Fan y Big had finally
been accurately surveyed.
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| The descent route over Craig y Fan Ddu |
Survey Result:
Waun Rydd
Bwlch Height: 599.5m (converted to OSGM15)
Bwlch Grid Reference: SO 03161 20517
Drop: 169.7m
Fan y Big
Summit Height: 716.7m (converted to OSGM15, average of three summit surveys [two on 30.06.18 and the third on 21.08.18]) (significant height revision)
Summit Grid Reference: SO 03652 20658
Bwlch Height: 688.2m (converted to OSGM15, average of two
bwlch surveys)
Bwlch Grid Reference: SO 03773 19876
Drop: 28.5m (700m Twmpau reclassified to 700m Sub-Twmpau confirmed) (Hewitt deletion) (Simm reclassified to Subsimm)
Gwaun Cerrig Llwydion
Summit Height: 729.2m (converted to OSGM15)
Summit Grid Reference: SO 04140 19665
Bwlch Height: 715.1m (converted to OSGM15)
Bwlch Grid Reference: SO 04562 19624
Drop: 14.0m (500m Sub-Uchaf status confirmed)
Dominance: 1.92%
Craig Gwrelyg (significant name change)
Summit Height: 753.9m (converted to OSGM15)
Summit Grid Reference: SO 05521 20383
Bwlch Height: 735.1m (converted to OSGM15)
Bwlch Grid Reference: SO 05763 20570
Drop: 18.9m (Uchaf and Pellennig status confirmed)
Dominance: 2.50%
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