Thack Moor (NY 611 462) – SubHewitt reclassified to Hewitt
This is one in a series of retrospective Hill
Reclassification posts that detail hills whose status has altered in the
listing of the English Hewitts (an acronym for Hill in England, Wales or Ireland over Two Thousand feet high). These reclassification posts will give details
of hills where I have had direct association with their change of status, and
they will tie in with a forthcoming Change Register giving detail to this list
and its alterations since first publication.
The listing of English Hewitts was published in booklet format by TACit Tables in June 1997 and
entitled The Hewitts and Marilyns of England. This list evolved out of The Absolute Summits
of England and Wales which were known as the Sweats (an acronym for Summits in Wales and England Above Two-thousand FEET) and which was published by Cicerone Press in
1992 in the book entitled The Relative Hills
of Britain. The list compiler for
the Hewitts and the preceding Sweats is Alan Dawson.
When the English Hewitts list was published in booklet format
there were 178 qualifying hills listed with their criteria being any English hill
at or above 2000ft (609.6m) in height with 30m minimum drop, accompanying the
main list are two sub category’s entitled SubHewitts, with the two sets of criteria
being any English hill at or above 600m and below 2000ft (609.6m) in height
that have a minimum drop of 30m and any English hill at or above 2000ft
(609.6m) in height with 20m or more and below 30m of drop.
 |
| The Hewtts and Marilyns of England by Alan Dawson |
The details for the hill reclassification appear below:
The name of the hill is Thack Moor (having previously been
listed as Renwick Fell), and it is situated in the extended Cross Fell group of
hills in the northern Pennines, and is positioned with the A686 road to its south-east
and the A689 road to its north-east, and has the small town of Alston towards the
east and the small community of Renwick towards the south south-west.
 |
| Thack Moor (NY 611 462) |
Prior to this hill’s reclassification to Hewitt status it was
listed as a SubHewitt with an estimated c 57m of drop based on the 609m summit
spot height that appeared on the Ordnance Survey 1:50,000 Landranger and
1:25,000 Explorer maps of the day and an estimated col height of c 552m.
As its 609m summit spot height was near the benchmark height
of 2000ft (609.6m) it was prioritised for a GNSS survey and this took place on
the 22nd August 2012. The
hill was surveyed by John Barnard, Graham Jackson and Myrddyn Phillips using a
Leica 530 and two hours of data were gathered, resulting in a summit height at
that time of 609.645m.
 |
| Gathering data with the Leica 530 during the first summit survey of Thack Moor |
As this result was so close to the benchmark height of 2000ft
(609.6m) it was decided to re-visit and gather a further four hours of data. The second survey was conducted on the 3rd
March 2013 by John Barnard, Graham Jackson and Myrddyn Phillips using a Leica
GS15, with Bob Smith editor of Grough joining us to write a feature on the
survey, and by Aled Williams who also joined us on the summit. The survey result at that time came to
609.625m which when converted using OSGM15 resulted in a summit height of 609.65m,
which is higher than the minimum 2000ft (609.6m) height required for Hewitt
status.
 |
| Gathering data with the Leica GS15 during the second summit survey of Thack Moor |
The reclassification of this hill from Sub-Hewitt to Hewitt
status was accepted by the list author and its new classification augmented in
to the listing of the Hewitts in April 2013.
The full details for the hill are:
Name: Thack Moor
OS 1:50,000 map: 86
OS 1:25,000 map: 31
Summit Height: 609.65m
(converted to OSGM15)
Summit Grid Reference:
NY 61166 46278
Col Height: 552m
Col Grid Reference: NY
636 456
Drop: 58m
Myrddyn Phillips (June 2019)
No comments:
Post a Comment