Mapping Mountains – Summit Relocations – The Welsh P15s

Ffridd Cadwaladr (SH 810 660) 

There has been a Summit Relocation to a hill that is listed in the The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Ffridd Cadwaladr (SH 810 660)

The criteria for the list that this summit relocation applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is now listed by is Ffridd Cadwaladr, and this was derived from the Tithe map, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned encircled by minor roads with the A470 road farther to its west and the A548 road farther to its south and the B5113 road farther to its east, and has the town of Llanrwst towards the south south-west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with 19m of drop, based on the 216m summit spot height positioned at SH 81131 65950 and the 197m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map. 

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

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.

LIDAR analysis gives the highest ground on this hill as 216.4m positioned at SH 81132 65959.  However, this is to the top of a structure that contouring implies resembles a covered reservoir, and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Ffridd Cadwaladr (SH 810 660)

The height produced by LIDAR analysis to the natural summit of this hill is 215.7m and is positioned at SH 81092 66027, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or the listing of a new twin summit or de-twinning of a summit, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 215.7m and is positioned at SH 81092 66027, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is approximately 68 metres north north-westward from where the high point of the structure and spot height are positioned and is also positioned in a different field. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Ffridd Cadwaladr 

OS 1:50,000 map:  116

Summit Height:  215.7m (LIDAR)                                                           

Summit Grid Reference (New Position):  SH 81092 66027 (LIDAR)                                                  

Bwlch Height:  198.3m (LIDAR) 

Bwlch Grid Reference:  SH 81357 65646 (LIDAR) 

Drop:  17.4m (LIDAR) 

 

Myrddyn Phillips (January 2026)