Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Cefn y Cerrig (SH 674 545) – Welsh Highland Sub addition 

There has been an addition 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. 

Cefn y Cerrig (SH 674 545) (Photo: Aled Williams)

The criteria for the list that this addition 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 Cefn y Cerrig and it is adjoined to the Moel Siabod group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A2), and it is positioned with the A4086 road to its north, the A498 road to its west and the A470 road to its south-east, and has the village of Capel Curig towards the north-east. 

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

Prior to the survey with the Trimble GeoXH 6000 this hill was initially listed with an estimated c 9m of drop, based on the 502m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 493m bwlch height, based on interpolation of 10m contouring between 490m – 500m. 

The Trimble GeoXH 6000 gathering data at the summit of Cefn y Cerrig.  (Photo: Aled Williams)

Therefore, the addition of this hill to Welsh Highland Sub status is due to a Trimble GeoXH 6000 survey, resulting in a 502.0m summit height and a 491.2m bwlch height, with these values giving this hill 10.8m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Moel Siabod

Name:  Cefn y Cerrig

OS 1:50,000 map:  115

Summit Height:  502.0m (converted to OSGM15)

Summit Grid Reference:  SH 67480 54509

Bwlch Height:  491.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 67511 54413   

Drop:  10.8m 

 

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 (May 2023)