Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

 

Pt. 844.2m (SH 869 246) – 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 LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pt. 844.2m (SH 869 246)

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 hill is being listed by the point (Pt. 844.2m) notation and it is adjoined to the Aran Fawddwy group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with the A494 road to its north-west and a minor road to its north-east, and has the village of Llanuwchllyn towards the north.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 10m of drop, based on the 844m summit spot height that appeared on the enlarged scale Ordnance Survey map available online and an estimated c 834m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

When the sub list was updated with details from basic levelling surveys conducted by Myrddyn Phillips the details for this hill were re-evaluated and it was listed with 8.5m of drop, based on a basic levelling survey conducted on the 19.09.98 which gave this hill 28ft of drop, resulting in the deletion of this hill from the sub list.

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 addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in an 844.2m summit height and an 833.6m bwlch height, with these values giving this hill 10.5m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Aran Fawddwy

Name:  Pt. 844.2m

OS 1:50,000 map:  124, 125

Summit Height:  844.2m (LIDAR)

Summit Grid Reference:  SH 86926 24690 (LIDAR)

Bwlch Height:  833.6m (LIDAR)

Bwlch Grid Reference:  SH 86852 24656 (LIDAR)   

Drop:  10.5m (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 (October 2023)