Tuesday, 11 August 2015

Mapping Mountains – Hill Reclassifications – Yr Uchafion

Pt. 649.8m (SH 660 452) - Uchaf reclassified to 500m Sub-Uchaf  

There has been a reclassification of an Uchaf to a 500m Sub-Uchaf due to a survey conducted by G&J Surveys.  Yr Uchafion is the informal title for the ‘Welsh 500m P15s’, a list jointly compiled with Aled Williams that takes in all hills in Wales at or above 500m that have a minimum of 15m of drop.  Details relating to this list are due to be published on the Mapping Mountains site in the near future.

The hill is situated in the Moelwynion and is positioned to the north of Moelwyn Mawr; which is its Cardinal Hill.  It can be easily accessed from the small communities of Croesor and Tanygrisiau; which are to the west and east respectively.

The hill is unnamed on Ordnance Survey maps, and therefore we are currently adopting the point / pwynt (Pt.) notation for it; this neutral protocol uses the summit height and therefore we have listed the hill as Pt. 649.8m.  However, this is only temporary as a locally known name is known by the authors, which will be used when the list receives full publication.

Pt. 649.8m was previously listed as having 15m of drop based on a series of Basic Levelling Surveys (BLS) conducted by Myrddyn Phillips in 1998, with the results sent to John and Anne Nuttall for their 2,000ft Welsh list of mountains.  When accepted into the Nuttalls list John and Anne coined the name Moelwyn Mawr North Ridge Top for this hill.  However,  its marginal status meant that it was always a prime candidate for being accurately surveyed, and this was subsequently done using two methods:  a line survey; the more accurate technique giving a drop of 14.8m, and GPS-based surveys, with the Leica GS15 also giving a drop of 14.8m and the Trimble GeoXH 6000 giving 14.9m.

This now revises the total of Uchaf hills which will be detailed in a future blog post, with the hill now listed as a 500m Sub-Uchaf.

The full details for the hill are:

Cardinal Hill:  Moelwyn Mawr

Summit Height:  649.8m (converted to OSGM15)

Name:  Pt. 649.8m

OS 1:50,000 map:  115

Summit Grid Reference:  SH 660 452

Drop:  14.8m

Pt. 649.8m on the right of photo with Moelwyn Mawr on the left towering over it

For details on the survey that reclassified this hill to 500m Sub-Uchaf status please click {here}

Myrddyn Phillips and Aled Williams (June 2015)

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