Mapping Mountains – Hill Reclassifications – Y Pedwarau

Clogau (SJ 184 462) – 400m Sub-Pedwar addition

There has been an addition to the listing of Y Pedwarau due to analysis of data on the OS Maps website, which is the recent replacement for OS Get-a-map.

Clogau (SJ 184 462)

The criteria for the list that this addition applies to are:

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Clogau, and it is adjoined to the Moel y Gamelin group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A542 road to its north-east, the A5104 road to its north-west and the A5 road to its south, and has the town of Llangollen towards the south-east.

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

Prior to analysis of data on OS Maps this hill was listed with 17m of drop based on the 455m summit spot height that appears on contemporary Ordnance Survey 1:25,000 Explorer maps and a bwlch height of 438m that appears as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

Extract from the OS Maps website

The addition of Clogau to 400m Sub-Pedwar status is due to the analysis of data on the OS Maps website.  This hill is now listed with an estimated c 460m summit height based on a 460m uppermost contour ring and an estimated bwlch height of c 439m based on bwlch contouring between 435m – 440m, with these values giving this hill c 21m of drop which is sufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Moel y Gamelin 

Name:  Clogau

OS 1:50,000 map:  116

Summit Height:  c 460m (interpolation)

Summit Grid Reference:  SJ 18455 46229 (interpolation)

Bwlch Height:  c 439m (interpolation)

Bwlch Grid Reference:  SJ 18304 46343 (interpolation)

Drop:  c 21m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (December 2019)