31.08.18 Carnedd Llywelyn (SH 683 643, only bwlch
surveyed)
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| The critical bwlch of Carnedd Llywelyn |
Having visited Foel Lwyd
and Tal y Fan surveying their bylchau and summits I now had an appointment with
Janet Ruth Davies, who is a research photographer. We met outside the Moel Siabod café in Capel
Curig and sat in the afternoon sunshine with what looked like the world’s
largest scone.
Janet contacted me a few
weeks ago and expressed interest in the lines of least resistance, which is the
phrase I used to describe how the hill to hill and valley to valley traverse
meet and form a critical bwlch. If
weather permitted I suggested we could visit the critical bwlch of Carnedd
Llywelyn and Trimble it.
Leaving the café we took
two cars toward the small car park adjoined to Gwern Gof Uchaf, a farm that has
camping facilities beautifully positioned near the base of Tryfan. On the way up the A5 cars driving in the opposite
direction were flashing their lights, and ahead grey smoke indicated that
something was ablaze, it was a car and it looked as if it may explode at any
minute as I drove past with flames leaping out of its bonnet.
Thankfully by the time
we parked and sorted our gear a fire engine had arrived to douse the flames,
but this remained as a near backdrop during the time we were at the bwlch.
A track leaves the
outskirts of Gwern Gof Uchaf leading toward Capel Curig, this would have been
the old road before the A5 was constructed, it led eastward and we followed it
as far as another indistinct track that headed a short distance northward
toward the busy road where cars were now stationary as the police and fire
brigade dealt with the remnants of the forlorn looking burnt out car.
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| Heading toward the bwlch |
The critical bwlch was
only a short distance from where we now were, and I used the Trimble as a
hand-held device to zero in to its critical point. This proved unsurprisingly to be positioned
beside a bog.
Having located the
position of the critical bwlch which had previously been documented from LIDAR
analysis conducted by Aled Williams, I positioned the Trimble atop my rucksack
and once the 0.1m accuracy level was attained before data should be logged, I
activated the equipment to gather data.
It then stood in place for just over an hour quietly beeping away
gathering individual data points, one every second, with 3,650 gathered in all.
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| Gathering data at the critical bwlch of Carnedd Llywelyn |
During this time conversation
between Jan and I flowed, and the intensity of the early evening light
increased with beautiful colour highlighting the first bronzed tinges of moor
grass as summer greenness ebbs in to autumn’s great colour show.
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| The Trimble set-up position at the critical bwlch of Carnedd Llywelyn |
Behind us Tryfan became
a silhouetted giant with a backdrop of sky that slowly cascaded in to evening
light as slithered cloud accentuated the setting sun.
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| Jan with the ever present and distinct profile of Tryfan in the background |
By now an evening chill
had set in, and as Janet and I had exhausted our photographic stock I headed
toward the Trimble to close it down. Its
hour long data set is the longest I’ve yet gathered. It was only a short walk back to our awaiting
cars and I waved Jan off before heading down the A5 toward home.
Postscript
Since the bwlch survey of this hill with the Trimble GeoXH 6000 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 this hill has been analysed using this technique, resulting in the LIDAR height and position for its summit being used.
Survey Result:
Carnedd Llywelyn
Summit Height: 1062.1m (LIDAR)
Summit Grid Reference: SH 68375 64349 (LIDAR)
Bwlch Height: 313.7m (converted to OSGM15, Trimble GeoXH 6000)
Bwlch Grid Reference: SH 67558 60463 (Trimble GeoXH 6000)
Drop: 748.3m (LIDAR summit and Trimble GeoXH 6000 bwlch)
Dominance: 70.46%
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