Mapping Mountains - Hill Reclassifications - The Welsh Highlands - Uchafion Cymru

 

The Welsh Highlands - Uchafion Cymru – Hill Reclassifications

The Welsh 500m P15s are the Welsh hills at or above 500m in height that have a minimum drop of 15m.  Accompanying the main P15 list are three sub lists; these are the 500m Subs, 490m Subs and the Double Subs with their criteria detailed in the respective Change Registers which are linked in their above titles, with details to this list given in the Introduction that was published on Mapping Mountains in November 2015.

The list is co-authored by Myrddyn Phillips and Aled Williams and the posts that have appeared on Mapping Mountains detailing the additions, reclassifications and deletions to the main P15 list and the sub lists appear below presented chronologically in receding order.

Postscript: On the 7^th January 2023 it was announced that the sub hills accompanying the main listing of the Welsh Highlands – Uchafion Cymru now take in just one category, this category is entitled the Welsh Highland Subs.  The criteria for which are all Welsh hills at and above 500m in height with 10m or more and below 15m of drop.

Therefore, the 490m Subs and 490m Double Subs have been dispensed with and the criteria for the 500m Subs that included Welsh hills with 14m or more and below 15m of drop, have been amended to include Welsh hills with 10m or more and below 15m of drop and their title changed to the Welsh Highland Subs.

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Pt. 914.9m (SH 659 585) – Welsh Highland Sub addition (114th reclassification)

Survey post for Pt. 914.9m

Significant Height Revisions post for Pt. 914.9m

 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Aled Williams. 

Pt. 914.9m (SH 659 585).  Photo: Aled Williams

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The hill is being listed by the point (Pt. 914.9m) notation, and it is adjoined to the Glyder Fawr group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A5 road to its north and the A4086 road to its south, and has the village of Capel Curig towards the east. 

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

When the initial P10 sub list was completed in June 2020 this hill was listed with 9.4m of drop, based on a 31ft basic levelling survey conducted by Myrddyn Phillips on the 02.05.99. 

Gathering data at the summit of Pt. 914.9m (SH 659 585).  Photo: Aled Williams

The hill was subsequently analysed via LIDAR by Aled Williams, resulting in a 913.9m summit height and a 905.1m bwlch height, with these values giving this hill 8.8m of drop, which was insufficient for it to be classified as a Welsh Highland Sub.  However, with the drop value relatively close to the qualifying criterion of 10m this hill was prioritised for a survey with the Trimble GeoXH 6000. 

Gathering data at the bwlch of Pt. 914.9m (SH 659 585).  Photo: Aled Williams

Therefore, the addition of this hill to Welsh Highland Sub status is due to a Trimble GeoXH 6000 survey, resulting in a 914.9m summit height and a 904.4m bwlch height, with these values giving this hill 10.5m of drop, which is sufficient for it to be classifie as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Glyder Fawr

Name:  Pt. 914.9m           

OS 1:50,000 map:  115

Summit Height:  914.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 65981 58563 (Trimble GeoXH 6000)

Bwlch Height:  904.4m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 65982 58556 (Trimble GeoXH 6000)   

Drop:  10.5m (Trimble GeoXH 6000) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (November 2024)

 

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Pen Tyrau (SH 837 382) – Welsh Highland Sub addition (113th reclassification)

Survey post for Pen Tyrau

 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Aled Williams. 

Pen Tyrau (SH 837 382).  Photo: Aled Williams

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Pen Tyrau, and it is adjoined to the Arenig Fawr group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with a minor road and the A4212 road to its north, and has the town of Y Bala towards the east south-east. 

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

The status of this hill has a convoluted history as it was originally listed with less than the required 10m minimum drop to qualify for sub status, and then included when the initial P10 sub list was completed in June 2020 and listed with 10.4m of drop, based on a basic levelling survey conducted by Myrddyn Phillips on the 14.09.98, and listed with a 697m summit height a 687m bwlch height, with an accompanying note stating that analysis of numerical data on various scales of Ordnance Survey maps give this hill an estimated c 9m of drop.  Therefore, it was included as a Welsh Highland Sub when the drop value of the subs was agreed upon and revised in July 2020. 

The Trimble GeoXH 6000 gathering data at the summit of Pen Tyrau.  Photo: Aled Williams

The hill was subsequently analysed via LIDAR by Aled Williams, resulting in a 697.8m summit height and a 688.1m bwlch height, with these values giving this hill 9.7m of drop, which is insufficient for it to be classified as a Welsh Highland Sub.  However, with the drop value relatively close to the qualifying criterion of 10m this hill was prioritised for a survey with the Trimble GeoXH 6000. 

The Trimble GeoXH 6000 gathering data at the bwlch of Pen Tyrau.  Photo: Aled Williams

Therefore, the addition of this hill to Welsh Highland Sub status is due to a Trimble GeoXH 6000 survey, resulting in a 697.4m summit height and a 687.4m bwlch height, with these values giving this hill 10.0m of drop, which is sufficient for it to be reinstated as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Arenig Fawr

Name:  Pen Tyrau           

OS 1:50,000 map:  124, 125

Summit Height:  697.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 83737 38250 (Trimble GeoXH 6000)

Bwlch Height:  687.4m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 83601 38142 (Trimble GeoXH 6000)   

Drop:  10.0m (Trimble GeoXH 6000) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (November 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Clipiau Duon (SH 900 227) – Welsh Highland Sub addition (112th reclassification)

 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Clipiau Duon (SH 900 227)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Clipiau Duon and it is adjoined to the Esgeiriau Gwynion group of hills, which are situated in the southern part of North Wales (Region A, Sub-Region A3), and it is positioned with the A494 road to its north-west and a minor road to its east, and has the village of Llanymawddwy towards the south.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 9m of drop, based on an estimated c 585m summit height and an estimated c 576m bwlch height, with both heights based on interpolation of 5m contouring that appeared on online mapping. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in a 586.3m summit height and a 576.1m bwlch height, with these values giving this hill 10.2m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Esgeiriau Gwynion

Name:  Clipiau Duon      

OS 1:50,000 map:  125

Summit Height:  586.3m (LIDAR)

Summit Grid Reference:  SH 90074 22779 (LIDAR)

Bwlch Height:  576.1m (LIDAR)

Bwlch Grid Reference:  SH 89864 22477 (LIDAR)   

Drop:  10.2m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Cefn Tyle Brych (SN 903 014) – Welsh Highland Sub deletion (111th reclassification)

 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Cefn Tyle Brych (SN 903 014)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Cefn Tyle Brych and it is adjoined to the Craig y Llyn group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A465 road to its north and the A4061 road to its east, and has the village of Treherbert towards the south-east.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 11m of drop, based on a 539m summit height and an estimated c 528m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 538.5m summit height and a 528.7m bwlch height, with these values giving this hill 9.8m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Craig y Llyn

Name:  Cefn Tyle Brych

OS 1:50,000 map:  170

Summit Height:  538.5m (LIDAR)

Summit Grid Reference:  SN 90321 01411 (LIDAR)

Bwlch Height:  528.7m (LIDAR)

Bwlch Grid Reference:  SN 90482 01905 (LIDAR)   

Drop:  9.8m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Pt. 557.6m (SO 023 822) – Welsh Highland Sub deletion (110th reclassification)

 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pt. 557.6m (SO 023 822)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The hill is being listed by the point (Pt. 557.6m) notation, and it is adjoined to the Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its north-west, south-west and north-east, and the B4518 and A470 roads to its west and the A483 road to its east, and has the town of Llanidloes towards the west north-west. 

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

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 11m of drop, based on the 558m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 547m bwlch height, based on the 1796ft (547.4m) height that appears on the Ordnance Survey series of Six-Inch maps. 

Extract from the Ordnance Survey series of Six-Inch maps

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 557.6m summit height and a 547.8m bwlch height, with these values giving this hill 9.8m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Hirddywel

Name:  Pt. 557.6m

OS 1:50,000 map:  136

Summit Height:  557.6m (LIDAR)

Summit Grid Reference:  SO 02324 82248 (LIDAR)

Bwlch Height:  547.8m (LIDAR)

Bwlch Grid Reference:  SO 02100 81851 (LIDAR)   

Drop:  9.8m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Esgair Dafydd (SN 836 453) – Welsh Highland Sub deletion (109th reclassification)

 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Esgair Dafydd (SN 836 453)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Esgair Dafydd and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with the A483 road to its south-east, and has the town of Llanwrtyd towards the east north-east.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 11m of drop, based on the 505m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 494m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 504.5m summit height and a 494.9m bwlch height, with these values giving this hill 9.5m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Drygarn Fawr

Name:  Esgair Dafydd

OS 1:50,000 map:  147

Summit Height:  504.5m (LIDAR)

Summit Grid Reference:  SN 83641 45366 (LIDAR)

Bwlch Height:  494.9m (LIDAR)

Bwlch Grid Reference:  SN 83970 45692 (LIDAR)   

Drop:  9.5m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Pt. 509.8m (SN 827 479) – Welsh Highland Sub addition (108th reclassification)

 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pt. 509.8m (SN 827 479)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The hill is being listed by the point (Pt. 509.8m) notation, and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north-west and east, and the A483 road to its south-east, and has the town of Llanwrtyd towards the east south-east.

When the initial P10 sub list was completed in June 2020 this hill was not listed as contour configuration did not give it sufficient interpolated drop for it to be included, with the contemporary Ordnance Survey 1:25,000 Explorer map having an uppermost 500m ring contour that also connects with its critical bwlch. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in a 509.8m summit height and a 499.5m bwlch height, with these values giving this hill 10.3m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Drygarn Fawr

Name:  Pt. 509.8m

OS 1:50,000 map:  147

Summit Height:  509.8m (LIDAR)

Summit Grid Reference:  SN 82700 47937 (LIDAR)

Bwlch Height:  499.5m (LIDAR)

Bwlch Grid Reference:  SN 82706 47648 (LIDAR)   

Drop:  10.3m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Carreg Wen Fawr (SN 820 624) – Welsh Highland Sub deletion (107th reclassification)

 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Carreg Wen Fawr (SN 820 624)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Carreg Wen Fawr and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its east and south, and has the village of Pontrhydfendigaid towards the west north-west. 

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

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 10m of drop, based on the 527m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 517m bwlch height, based on interpolation of 5m contouring that appeared on online mapping, with an accompanying note stating:

Summit-area height of 1726ft (526.1m) on OS 6" Map (1888) is in a different position to the 527m height given on paper and enlarged-scale online OS maps. 

Extract from the Ordnance Survey series of Six-Inch maps

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 526.0m summit height and a 516.6m bwlch height, with these values giving this hill 9.4m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Drygarn Fawr

Name:  Carreg Wen Fawr

OS 1:50,000 map:  147

Summit Height:  526.0m (LIDAR)

Summit Grid Reference:  SN 82080 62445 (LIDAR)

Bwlch Height:  516.6m (LIDAR)

Bwlch Grid Reference:  SN 82049 62279 (LIDAR)   

Drop:  9.4m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)

Mapping Mountains - Hill Reclassifications - Welsh Highlands - Uchafion Cymru

Graig Fawr (SN 776 685) – Welsh Highland Sub addition (106th reclassification)

 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Graig Fawr (SN 776 685)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Graig Fawr and it is adjoined to the Carn yr Hyrddod group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with the B4343 road to its west and a minor road to its south, and has the village of Pont-rhyd-y-groes towards the north-west.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 8m of drop, based on a 502m summit height and an estimated c 494m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in a 502.4m summit height and a 492.0m bwlch height, with these values giving this hill 10.4m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Carn yr Hyrddod

Name:  Graig Fawr

OS 1:50,000 map:  135, 147

Summit Height:  502.4m (LIDAR)

Summit Grid Reference:  SN 77653 68592 (LIDAR)

Bwlch Height:  492.0m (LIDAR)

Bwlch Grid Reference:  SN 77643 68675 (LIDAR)   

Drop:  10.4m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (January 2024)