A new metric “Super Mountain” was revealed by G & J Surveys at a press conference in Maentwrog, Snowdonia yesterday. The vast majority of the UK’s mountains with summits of over 1 000 metres are in the Scottish highlands with previously only four other summits – all in Snowdonia – confirmed as over this height. Glyder Fawr, previously recorded as 999 metres by Ordnance Survey has been measured as 1000.8 metres in height making it a “Super Mountain”.
G & J team on Glyder Fawr summit – photo courtesy G & J Surveys
Mountain survey specialists G & J Surveys (Graham Jackson, John Barnard & Myrddyn Phillips) were aware that very few of the UK’s “thousander” mountains were located outside the Scottish Highlands. At his presentation announcing the survey results, Myrddyn Phillips explained that in the vast area of Wales, England and Northern Ireland summits over 1 000 metres are very rare. Previously only four summits have been identified – all in Snowdonia. These summits are:
- Snowdon/Yr Wyddfa with 1 085 m
- Crib y Ddysgl with 1 065 m
- Carnedd Llewelyn with 1 064 m
- Carnedd Dafydd with 1 044 m
Since peaks with summits over 1 000 metres are so rare outside Scotland, G & J surveys have devised the term “Super Mountain” to describe them. They noticed that one major Welsh peak – Glyder Fawr – has a height measured by Ordnance Survey at 999 metres. Ordnance Survey has used aerial surveying techniques to measure summit heights and these have an accuracy of ± 3 metres meaning that the height could be anywhere between 996 and 1002 metres. Since this could mean that Glyder Fawr could meet the critieria for a “Super Mountain”. Myrddyn Phillips added that G & J Surveys have GPS-based surveying equipment that can measure heights to an accuracy of ± 5 cm and thus hoped to determine whether or not Glyder Fawr’s summit was over one thousand metres.
Glyder Fawr from Glyder Fach: photo Roddy Urquhart
The Glyder range (Glyder Fawr and Glyder Fach) is spectacular with a ‘lunar landscape’ of grey rocks with many pinnacles. Glyder Fawr has two tors of similar height so G & J Surveys measured both in order to be sure of measuring the true summit. The tor closer to Lake Ogwen was measured as 1.4 metres higher than the other. This tor has two pinnacles and one was found to be 2 millimetres higher than the other! The summit height of Glyder Fawr – after running measurements for four hours – was determined to be 1000.8 metres making it the fifth “Super Mountain”.
Mark Greaves of Ordnance Survey confirmed the data presented. He said that heights such as 999 metres for Glyder Fawr should not be regarded as “wrong” but simply the best estimate given the surveying technique used. He confirmed that the measuring equipments used by G & J Surveys was very accurate and said that Ordnance Survey accepted the new height for Glyder Fawr. The new height (which will be marked as 1 001 metres) will appear in digital maps in about one month and in the upcoming reprints of 1:50000 and 1:25000 maps.
The new measurements also impact the UK Prominent Peaks classification devised by Jim Bloomer and Roddy Urquhart of UK Metric Association. UKMA was invited to make a presentation at the press conference and Roddy explained that metric maps have a surprisingly long history in the UK. The currently used 1:50000 scale (equivalent to 2 cm for 1 km) was first proposed by map-making pioneer William Roy in the 18th Century. The kilometre-based National Grid was proposed by the Davidson Committee in 1935 and metric contours were used on some maps by Ordnance Survey by 1956.
UK Prominent Peak height breakpoints align with major contours
Unlike traditional hillwalking lists with height breakpoints at imperial heights such as two thousand or three thousand feet, the UK Prominent Peaks classification uses break points that line up with modern metric maps. This uses break points at 500, 750 and 1 000 metres which are easily found contours. The new survey results on Glyder Fawr mean that the peak is reclassified from an ‘H750’ (with height in the range 750-999 metres) to an ‘H1000’ (height of 1 000 metres and above). Roddy explained that Glyder Fawr is now the 134th Prominent Thousander peak in the UK. (Note that H1000 has a more restrictive definition than “Super Mountain” as it must have a height of at least one thousand metres and a prominence of at least 100 metres).
In addition the Welsh 1000m Peaks Race may be impacted. Kate Williams of the Gorphwysfa Club explained that the current route covers the previously known four “Super Mountains” and crosses the Glyder ridge simply as a means of going between the Carneddau and Snowdon ranges. She explained that re-routing the race to include Glyder Fawr would be more “satisfying” by being a more comprehensive 1 000 m route, but that organisational and safety issues would need to be reviewed before making a change.
Glyder Fawr is owned by the National Trust and spokesman Rhys Evans described the new survey announcement as a “historic day”.
Finally Emyr Williams Director of Land Management at the Snowdonia National Park Authority, who chaired the press conference, said: “We are extremely pleased that G & J Surveys have gone to so much trouble to ensuring a correct measurement for Glyder Fawr.The new measurement has new obligations for us as an Authority from a land conservation and management perspective. We now have a fifth peak in Snowdonia which is higher than 1000m and as a result, it is sure to attract more walkers to this area”.
The UK Prominent Peaks workbooks and maps will be updated shortly to reflect the new measurements of Glyder Fawr and an announcement will follow on this blog as soon as they are available.
Video coverage of G&J Surveys’ work on Glyder Fawr and the press conference is given on YouTube here.