Thursday, 26 January 2017

Change Register – Y Pedwarau – 390m Sub-Pedwarau


Change Register

Y Pedwarau – The 400m Hills of Wales

390m Sub-Pedwarau


Y Pedwarau are the Welsh hills at or above 400m and below 500m in height that have a minimum drop of 30m.  The list’s initial compilation was completed in November 2002 and entitled The 400m Peaks of Wales and was first published on 19th December 2002 on the RHB Yahoo Group file database along with the equivalent English and Manx hills, with the file entitled the 400m hills of England, Isle of Man and Wales, this file was uploaded by Rob Woodall who later augmented data from Clem Clements into the database.

Over subsequent years the listing now known as Y Pedwarau has been published on the v-g.me website and the 5everdene website in list format (22nd October 2004), available as a downloadable e-booklet and print-booklet version on the Europeaklist website (23rd May 2013), available as GPS Waypoints, Google mapping and online hill bagging tick lists on the Haroldstreet website (6th January 2014) and as of 30th January 2017 publication of Y Pedwarau commenced on the Mapping Mountains site.

The compilation that originated in 2002 and all subsequent publications of this list had an accompanying sub list that is now named the 400m Sub-Pedwarau.  However, it wasn’t until the Europeaklist publication and the subsequent Haroldstreet publication that the listing included two other sub categories; the 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau and this Change Register details those hills that are, or have been listed within the 390m Sub-Pedwar category.

The 390m Sub-Pedwarau are those hills that fail to meet the Pedwar qualification by 10m or less of height, these are the hills that are 390m or more and below 400m in height that have a minimum 30m of drop.

The 390m Sub-Pedwar hills first appeared as a category of hill in the May 2013 publication by Europeaklist, when this version of Y Pedwarau was published there were 39 hills listed that met the qualification for 390m Sub-Pedwar status, all of these hills were identified leading up to this publication, and after Y Pedwarau was later published on 6th January 2014 by Phil Newby on his Haroldstreet website all future updates to the list have been catalogued on the Mapping Mountains site.

With all updates to the list appearing on Mapping Mountains it became evident that keeping the list up-to-date if hosted on another person’s website was difficult to say the least, therefore on 30th January 2017 the Y Pedwarau list commenced publication on Mapping Mountains with five sub lists accompanying the main P30 Pedwar list.   

Since its original publication Y Pedwarau has changed greatly as the list is now co-authored with Aled Williams, and although the criteria has remained the same for the main P30 list, it now also includes two other sub categories; the 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau.  The listing also benefits from accurate surveys conducted by independent surveyors using GPS / GNSS receivers, an expanded range of Ordnance Survey maps available online and most recently, by analysis of LIDAR data enabling greater accuracy for numerical data.  However, it is not just numerical data that has seen this list develop since its first inception, it is also place-name data, and it was because of this and their mutual interest in hill lists that the authors first corresponded.  The listing is also gaining in popularity as there are now four known completers of Y Pedwarau with another ten people having completed 100 or more Pedwar hills.

It seems fitting that the list of Y Pedwarau – The 400m Hills of Wales – 390m Sub-Pedwarau should now benefit from a detailed Change Register, and although updates to this sub category have been detailed on the Mapping Mountains site, it is prudent for this Change Register to initially detail the changes to this sub list since the May 2013 publication by Europeaklist.

The Change Register to Y Pedwarau – The 400m Hills of Wales – 390m Sub-Pedwarau appears below with the reclassifications to the list being detailed chronologically in receding order. 



Change Register

Y Pedwarau – The 400m Hills of Wales

390m Sub-Pedwarau






Allt y Genlli    398.9m at SN 98508 95042


The reclassification of this hill to 390m Sub-Pedwar status was announced on Mapping Mountains on the 24.05.17, the hill was previously listed as a 390m Double Sub-Pedwar with 27m of drop based on the 394m summit spot height on the Ordnance Survey 1:25,000 Explorer map and the 367m bwlch spot height on the Ordnance Survey enlarged mapping hosted on the Geograph website.  This hill’s reclassification is dependent upon the analysis of LIDAR data by Aled Williams of it, and its southerly adjacent hill of Mynydd Garth Pwt, with the result being a swap in listed bwlch positions as the 398.9m summit height of Allt y Genlli is higher than the 397.8m summit height of Mynydd Garth Pwt, with the heights of the bylchau being 325.7m and 367.3m respectively, therefore the lower bwlch is the critical bwlch for the higher of the two hills, with these values giving Allt y Genlli 73.2m of drop which is sufficient for it to be reclassified as a 390m  Sub-Pedwar, and with 30.5m of drop Mynydd Garth Pwt also retains its 390m Sub-Pedwar status.  390m Sub-Pedwar total increases by one and confirmed as 38.





390m Sub-Pedwar total confirmed as 37.





Cefn Bach    389.4m at SO 00293 37291

The Trimble GeoXH 6000 gathering data at the summit of Cefn Bach

This hill’s deletion from the ranks of 390m Sub-Pedwarau was announced on Mapping Mountains on 22.01.17.  The hill had been listed as being 391m high with 55m of drop based on the summit spot height and the 336m bwlch spot height on Ordnance Survey maps, and it was prioritised for 390m Sub-Pedwar status in preference to its twin topped 391m map heighted northerly summit at SO 00375 38722 which was listed as a 390m Double Sub-Pedwar with c 22m of drop.  This southerly hill was subsequently surveyed by Myrddyn Phillips on the 18.08.15 with the Trimble GeoXH 6000, and the resulting 389.4m summit height and 54.4m bwlch height announced on the Mapping Mountains site on 22.09.15.  However, it wasn’t until this hill and its adjacent twin map heighted northerly summit was analysed with LIDAR data by Aled Williams that this hill was confirmed as being 0.2m higher than its northerly neighbour, with both the Trimble survey and the LIDAR data confirming that this hill is under the 390m threshold height which is insufficient for retention as a 390m Sub-Pedwar hill.  390m Sub-Pedwar total decreases by one and confirmed as 37.





Moel Fodiar    389.8m at SH 97828 68002

Moel Fodiar is the first hill deleted from the ranks of 390m Sub-Pedwarau since this sub category first appeared in the May 2013 Europeaklist publication

The first hill whose reclassification from a 390m Sub-Pedwar was due to a survey with the Trimble GeoXH 6000, with the change in status of this hill being announced on the Mapping Mountains site on 11.04.16.  The hill had been listed as being 390m high and with 117m of drop based on the 390m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 273m bwlch spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.  The hill was subsequently surveyed with the Trimble GeoXH 6000 by Myrddyn Phillips on 05.04.16, resulting in a 389.8m summit height, which is insufficient for the hill to retain its 390m Sub-Pedwar status.  390m Sub-Pedwar total decreases by one and confirmed as 38.



6th January 2014 – Haroldstreet publishes Y Pedwarau. 

390m Sub-Pedwar total confirmed as 39.




23rd May 2013 – Europeaklist publishes Y Pedwarau. 

390m Sub-Pedwar total confirmed as 39.






Myrddyn Phillips and Aled Williams (January 2017)


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