Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Carnedd Fach (SH 658 626) – 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 LIDAR analysis conducted by Aled Williams. 

LIDAR image of Carnedd Fach (SH 658 626)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Carnedd Fach and it is adjoined to the Carnedd Llywelyn 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 west and south, and has the town of Bethesda towards the north-west.

When the original list that later became known as the Welsh Highlands – Uchafion Cymru was first compiled, this hill was not included in the accompanying sub list, based on a basic levelling survey conducted by Myrddyn Phillips on the 25.07.98, which resulted in a 9.6m drop value.                                                                                                                               

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

When the initial P10 sub list was completed in June 2020 this hill was listed as a Welsh Highland Sub with an estimated c 12m of drop, due to a misalignment of the basic levelling survey result with OS Maps data, and listed with a 966m summit height and an estimated c 954m bwlch height.

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 965.1m summit height and a 956.2m bwlch height, with these values giving this hill 8.9m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Carnedd Llywelyn

Name:  Carnedd Fach

OS 1:50,000 map:  115

Summit Height:  965.1m (LIDAR)

Summit Grid Reference:  SH 65808 62620 (LIDAR)

Bwlch Height:  956.2m (LIDAR)

Bwlch Grid Reference:  SH 65840 62664 (LIDAR)   

Drop:  8.9m (LIDAR) 

 

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 (June 2023)