Tuesday 5 April 2022

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales


Cefn Uchaf (SJ 249 402) – Sub-Trichant addition

There has been an addition to the list of Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data. 

The criteria for the list that this addition applies to are: 

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Cefn Uchaf and this was derived from the Ordnance Survey Draft Surveyors map, and it is adjoined to the Craig Berwyn group of hills, which are situated in the eastern part of North Wales (Region A, Sub-Region A3), and it is positioned encircled by minor roads with the A5 road farther to its north and the B4500 road farther to its south, and has the town of Llangollen towards the west north-west. 

Extract from the Ordnance Survey 1:25,000 Explorer map

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category. 

Extract from the Ordnance Survey 1:50,000 Landranger map

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 21m of drop, based on the 395m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger map and an estimated c 374m bwlch height, based on interpolation of 5m contouring between 370m – 375m, with the 395m summit height also given on the interactive mapping hosted on the WalkLakes website. 

Extract from the interactive mapping on the WalkLakes website

Therefore, the addition of this hill to Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 395m summit height and an estimated c 374m bwlch height, with these values giving this hill an estimated c 21m of drop, which is sufficient for it to be classified as a Sub-Trichant. 

 

The full details for the hill are: 

Group:  Craig Berwyn 

Name:  Cefn Uchaf 

OS 1:50,000 map:  117

Summit Height:  395m (spot height)                                                           

Summit Grid Reference:  SJ 24921 40228 (spot height) 

Bwlch Height:  c 374 (interpolation) 

Bwlch Grid Reference:  SJ 24502 40242 (interpolation) 

Drop:  c 21m (spot height summit and interpolated bwlch) 

 

Myrddyn Phillips (April 2022)

 

 

  

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