Thursday, 6 April 2023

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru


Craig Eigiau (SH 712 646) – 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. 

Craig Eigiau (SH 712 646) (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 Craig Eigiau 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 a minor road to its north-east, the A5 road to its south-west and the B5106 road and the A470 road to its east, and has the town of Llanrwst towards the east south-east. 

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

Prior to the survey with the Trimble GeoXH 6000 this hill was listed with 9.7m of drop, based on a 688.1m summit height and a 678.4m bwlch height, with both heights derived from LIDAR analysis conducted by Aled Williams.  Due to the marginal nature in the drop ascertained from LIDAR analysis, this hill was prioritised for a Trimble GeoXH 6000 survey and it is this result that is being prioritised. 

The Trimble GeoXH 6000 gathering data at the summit of Craig Eigiau (SH 712 646) (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 688.4m summit height and a 678.2m bwlch height, with these values giving this hill 10.2m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Carnedd Llywelyn

Name:  Craig Eigiau

OS 1:50,000 map:  115

Summit Height:  688.4m (converted to OSGM15)

Summit Grid Reference:  SH 71280 64670

Bwlch Height:  678.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 71218 64674   

Drop:  10.2m 

 

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 (April 2023)

  

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