Mapping Mountains – Hill Reclassifications – Y Pedwarau

Cefn Cynllaith (SN 892 515) – 400m Sub-Pedwar addition

There has been an addition to the listing of Y Pedwarau due to analysis of LIDAR data by Aled Williams.  Y Pedwarau is the title for the list of 400m hills of Wales and takes in all Welsh hills at or above 400m and below 500m in height that have a minimum 30m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and it commenced publication on Mapping Mountains on the 30.01.17.

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 qualification is all Welsh hills at or above 400m and below 500m in height with 20m or more and below 30m of drop.

Prior to analysis of LIDAR data the hill was listed with 16m of drop based on the 404m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 388m bwlch spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.

The name of the hill is Cefn Cynllaith and it is situated in the Elenydd range with its Cardinal Hill being Pen y Garn Goch (SN 884 502) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2).  The hill is positioned above the stream valleys of the Nant yr Annell to the north and the Nant Einon to the south, with the small community of Beulah towards its east.

As the summit of the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the nearest approach via a public footpath is from the south and over the Nant Einon to a track below the summit.  Alternatively a longer approach from the east via another public footpath leads to the same track just south of the summit.

The addition of Cefn Cynllaith to 400m Sub-Pedwar status is due to the 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 gives the hill the following details:

Cefn Cynllaith

Summit Height:  405.0m

Summit Grid Reference:  SN 89292 51575

Bwlch Height:  383.9m

Bwlch Grid Reference:  SN 89176 51655

Drop:  21.1m

Therefore, the 405.0m LIDAR data produced for the summit position at SN 89292 51575 and the 383.9m LIDAR data produced for the bwlch position at SN 89176 51655 gives this hill 21.1m of drop which is sufficient for its inclusion as a 400m Sub-Pedwar.

The full details for the hill are:

Cardinal Hill:  Pen y Garn Goch

Summit Height:  405.0m (LIDAR data)

Name:  Cefn Cynllaith

OS 1:50,000 map:  147

Summit Grid Reference:  SN 89292 51575

Drop:  21.1m (LIDAR data)

The total for Y Pedwarau remains at 442 hills with nine additions, and fourteen reclassifications to 400m Sub-Pedwar status since publication of the list by Europeaklist in May 2013.

The overall total for the 400m Sub-Pedwarau is now 220 with 27 hills being added and 20 hills being taken out of this category since publication of the list by Europeaklist in May 2013.

The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes detailed on the Mapping Mountains site, with the list also having commenced publication on Mapping Mountains on the 30.01.17.

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 (August 2017)