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

Mynydd Glan Llyn y Forwyn (SH 685 239) – Sub-Trichant reclassified to Trichant

There has been a reclassification 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 reclassification 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 13^th May 2017. 

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

The name the hill is listed by is Mynydd Glan Llyn y Forwyn, and it is adjoined to the Y Llethr group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A2), and it is positioned with the A496 road to its south and the A470 road to its east, and has the village of Ganllwyd towards the east. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 category, with an accompanying note stating; Two points of same height – other at SH687238. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current such as the interactive mapping on the Magic Maps and WalkLakes websites. 

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated against the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.  This mapping had many spot heights not on other publicly available maps and for this hill it had a 343m bwlch spot height and when coupled with the 378m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map, these values give this hill 35m of drop.

Therefore, the reclassification of this hill from Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 378m summit height and a 343m bwlch height, with these values giving this hill 35m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Y Llethr 

Name:  Mynydd Glan Llyn y Forwyn 

OS 1:50,000 map:  124

Summit Height:  378m (spot height)                                                           

Summit Grid Reference:  SH 68596 23970 (hand-held GPS via DoBIH) 

Bwlch Height:  343m (spot height) 

Bwlch Grid Reference:  SH 68817 23700 (spot height) 

Drop:  35m (spot height summit and bwlch) 

 

Myrddyn Phillips (January 2022)