Mapping Mountains – Hill Reclassifications – 100m Twmpau

Pentre Clawdd Gorse (SJ 311 442) - 100m Twmpau addition  

There has been an addition of a hill to the list of 100m Twmpau (thirty welsh metre prominences and upward) instigated by a summit survey with the Trimble GeoXH 6000 and subsequent LIDAR bwlch analysis.   The hill is situated to the east of the A483 road and to the north-east of Rhiwabon (Ruabon) in the eastern part of the Moel y Gamelin range of hills.

LIDAR image of Pentre Clawdd Gorse (SJ 311 442)

The Trimble GeoXH 6000 survey that initiated this hill’s addition to the 100m Twmpau list was conducted in the afternoon of the 23^th February 2016 on a beautiful winter’s day in good, dry and sunny conditions.

The name the hill is listed by is Pentre Clawdd Gorse and access to it is relatively easy as its summit is positioned on Wat’s Dyke, this ancient earthwork stretches from the Dee estuary in the north to Shropshire in the south, and public footpaths follow its course over this hill.

Pentre Clawdd Gorse is adjoined to the summit of Wynnstay Park (SJ 31001 42958) which is approximately one kilometre due south from it, with the latter having a 141m spot height given it on Ordnance Survey 1:25,000 Explorer maps.  The summit of Wynnstay Park was surveyed on the 20^th October 2015 with the Trimble GeoXH 6000 and subsequently analysed via LIDAR, resulting in a 141.2m summit height.

The survey with the Trimble GeoXH 6000 resulted in a summit height of 142.0m, giving Pentre Clawdd Gorse as 0.8m higher than Wynnstay Park.  The area of the bwlch was analysed via LIDAR resulting in a 109.8m height, with these values giving this hill 32.2m of drop, which is sufficient for this hill to be classified as a 100m Twmpau. 

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Pentre Clawdd Gorse

OS 1:50,000 map:  117

Summit Height:  142.0m (converted to OSGM15)

Summit Grid Reference:  SJ 31131 44252 

  

Bwlch Height:  109.8m (LIDAR)

Bwlch Grid Reference:  SJ 30789 44141 (LIDAR)

Drop:  32.2m (Trimble summit and LIDAR bwlch)

The summit of Pentre Clawdd Gorse (SJ 311 442) the new addition to the 100m Twmpau list

For details on the survey that resulted in this hill being added to the 100m Twmpau list please click {here} for summit and {here} for the bwlch survey.

Myrddyn Phillips (February 2016)