Monday, 16 January 2017

Mapping Mountains – Hill Reclassifications – Y Pellennig – The Remotest Hills of Wales

Pembrey Forest (SN 393 016) - Pellennig deletion

There has been a deletion of a hill from the list of Y Pellennig – The Remotest Hills of Wales, due to analysis of LIDAR data by Aled Williams.  The criteria for qualification as a Pellennig is any hill in Wales whose summit is at least 2.5km from the nearest paved public road and the hill having a minimum drop of 15m.  The list of Y Pellennig – The Remotest Hills of Wales is available as a downloadable e-booklet or print-booklet version on Mapping Mountains Publications with the up-to-date master list available on the Mapping Mountains site.

The hill is situated in the west south-western part of the Mynydd Sylen group of hills and as its name suggests; it is a part of a relatively large area of land comprising almost 2,500 acres of woodland whose south-western boundary borders sand dunes with the sea beyond.  Its Cardinal Hill is Mynydd Sylen (SN 515 080) and it is placed in the Region of South Wales (C-1).  The hill and conifer plantation is named the Pembrey Forest and it is situated with the community of Pen-bre and the town of Porth Tywyn (Burry Port) to its east south-east.   

The hill can be accessed from one of the main forest tracks that emerge out of the Pembrey Country Park to its south-east, or from a public footpath to its north that forms a part of the Wales Coastal Path.

The name of the hill is Pembrey Forest and it was listed as a Pellennig with 2.560km distance between its summit and the nearest paved public road and with c 18m of drop.  The previously listed summit is positioned at SN 390 021, this position is to one of five 25m ring contours that are shown on the Ordnance Survey 1:25,000 Explorer map, and importantly this ring contour is the furthest from any paved public road.

The deletion of Pembrey Forest from the listing of Pellennig hills is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data to the highest natural ground within the forest gives the hill the following details:

Pembrey Forest

Summit Height:   27.1m

Summit Grid Reference:  SN 39390 01694

Bwlch Height:  9.5m

Bwlch Grid Reference:  SN 38702 02181

Drop:  17.6m

Remoteness:  2.360km from SN 41696 02197 (does not qualify on distance) 

The bwlch position given above connects this hill to the Pembrey Forest Ski Slope, which is given a much larger 25m ring contour and also a 30m ring contour; although in all probability the summit has been altered during the building of the ski slope.  The critical bwlch for whichever high point is taken is positioned at SN 409 019 and is c 7m high.

The summit previously listed in the Y Pellennig list is to the north of the details to the hill given above, and its LIDAR data came to:

24.8m at SN 38984 02162

However, there is a higher summit in the vicinity of the old Pellennig summit and this hill’s details was also analysed with LIDAR data, these are given below:

Pembrey Forest

Summit Height:   25.7m

Summit Grid Reference:  SN 39118 02003

Bwlch Height:  13.4m

Bwlch Grid Reference:  SN 39288 01922

Drop:  12.3m (does not qualify on drop)

Aled’s analysis of LIDAR data gave the hill a 27.1m summit height at SN 39390 01694, and a 9.5m bwlch height at SN 38702 02181 (bwlch position connecting to probable artificial summit of ski slope), these values give this hill 17.6m of drop, and a 2.360km distance from the nearest paved public road which is insufficient for it to retain its Pellennig status.

This now brings the overall total for Y Pellennig to 168 hills for the Complete list (All Wales), with the total for the Mainland Wales list being 124 hills.  The Master List will be duly updated on the Mapping Mountains site.

The full details for the hill are:

Cardinal Hill:  Mynydd Sylen

Summit Height:  27.1m (LIDAR data)

Name:  Pembrey Forest

OS 1:50,000 map:  159

Summit Grid Reference:  SN 39390 01694 
Drop:  17.6m (LIDAR data)

Distance:  2.360km

The list of additions and deletions in the Pellennig list since the 1st edition of Y Pellennig – The Remotest Hills ills of wales of Wales was published by Europeaklist (1st edition, April 2015) is as follows:



Pembrey Forest (SN 393 016)

Y Pellennig – The Remotest Hills ills of wales of Wales is now published by Mapping Mountains Publications (2nd edition, July 2016).

Myrddyn Phillips and Aled Williams (January 2017)

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