Tryfan (SH 663 593) – Welsh Highland Sub
deletion
There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height
and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Aled Williams.
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Tryfan (SH 663 593) (Photo: Aled Williams) |
The criteria for the list that this deletion applies to are:
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Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams |
The name the hill is listed by is Tryfan and it is
adjoined to the Glyder Fawr group of hills, which are situated in the north-western part of North Wales (Region A,
Sub-Region A1), and it is positioned with the A5
road to its north and the A4086 road to its south, and has the village of Capel
Curig towards the east south-east.
When the initial P10 sub list was completed in
June 2020 this hill was not included.
Revision of the list based on basic levelling surveys conducted by
Myrddyn Phillips was completed the following month and this hill was then
listed with 10.0m of drop, based on a basic levelling survey conducted on the
01.05.98, and listed with a 910m summit height that appears as a spot height on
the Ordnance Survey 1:25,000 Explorer map and a 900m bwlch height, based on the
basic levelling survey result compared to the summit spot height.
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Extract from the Ordnance Survey 1:25,000 Explorer map |
Due to the marginal nature in both listed drop and
the accuracy of the surveying method that this was obtained from, this hill was
prioritised for a Trimble GeoXH 6000 survey and this has now taken place
resulting in its deletion from sub status.
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A precarious position for a survey - Trimble attached to a dog lead and held in situ (Photo: Aled Williams) |
Therefore, the deletion of this hill from Welsh
Highland Sub status is due to a Trimble GeoXH 6000 survey, resulting in a 910.8m
summit height and a 901.6m bwlch height, with these values giving this hill 9.2m
of drop, which is insufficient for it to be classified as a Welsh Highland Sub.
The full details for the hill are:
Group: Glyder Fawr
Name: Tryfan
OS 1:50,000 map: 115
Summit Height: 910.8m (converted
to OSGM15)
Summit Grid Reference:
SH 66393 59332
Bwlch Height: 901.6m (converted
to OSGM15)
Bwlch Grid Reference:
SH 66378 59359
Drop: 9.2m
For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru
reported on Mapping Mountains please consult the following Change Registers:
Welsh Highland P15s
Welsh Highland Subs
Aled Williams and Myrddyn Phillips (March 2023)
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