Llechwedd Du (SH 893 446) – 500m
Sub-Uchaf reclassified to Uchaf
THIS HILL HAS SUBSEQUENTLY BEEN RECLASSIFIED TO WELSH HIGHLAND SUB STATUS
There has been a reclassification to the listing of The Welsh Highlands – Uchafion Cymru due
to analysis of 5m contouring on the OS Maps website coupled with spot height
data on the contemporary Ordnance Survey 1:25,000 Explorer map.
The criteria for the list that this reclassification applies
to are:
The Welsh Highlands –
Uchafion Cymru
– This is the revised draft title for the Welsh 500m P15s list that takes
in all hills in Wales at or above 500m in height with 15m minimum drop. Accompanying the main list are three sub
lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category,
with this hill being reclassified from 500m Sub-Uchaf status, the criteria for
which are all Welsh hills at or above 500m in height with 14m or more and below
15m of drop. The list is co-authored by
Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.
The name of the hill is
Llechwedd Du and it is adjoined to the Arenig group of hills, which are situated in the central part of North
Wales (Region A, Sub-Region A3), and is positioned
with the A4212 road to its south, and the B4501 road to its east, and has the town
of Y Bala towards its south south-east and the village of Cerrigydrudion
towards the north-east.
When the original list of Welsh 500m P15s that
later became known as Yr Uchafion and
latterly as The Welsh Highlands –
Uchafion Cymru was compiled, this hill was included as a 500m Sub-Uchaf
with 14m of drop based on the 509m summit spot height that appears on the
Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 495m
bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
 |
| Extract from the Ordnance Survey 1:25,000 Explorer map |
The details for this hill were re-assessed when
the OS Maps website became available online.
This is the replacement for OS Get-a-map and has contours at 5m
intervals which are proving consistently more accurate compared to the 5m
contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and
the online Vector Map Local. This re-assessment
resulted in the hill being listed with c 16m of drop based on an estimated
summit height of c 511m from interpolation of the 510m uppermost contour and
the 495m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer
map.
 |
| Extract from the OS Maps website |
Therefore, the reclassification of this hill from
500m Sub-Uchaf to Uchaf status is due to an estimated summit height of c 511m based
on the 5m contours on the OS Maps website and the 495m bwlch spot height that
appears on the Ordnance Survey 1:25,000 Explorer map, with these values giving
this hill c 16m of drop, which is sufficient for it to be reclassified to Uchaf
status.
The full details for the hill are:
Group: Arenig
Name: Llechwedd Du
OS 1:50,000 map: 124,
125
Summit Height: c 511 (interpolation)
Summit Grid Reference:
SH 89377 44652 (spot height)
Bwlch Height: 495m (spot
height)
Bwlch Grid Reference:
SH 89128 44308 (spot height)
Drop: c 16m
For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru
reported on Mapping Mountains please consult the following Change Registers:
Aled Williams and Myrddyn Phillips (December 2019)
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