The first list to the Welsh
200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this
list preceded the list of TuMPs by nine years, the list proved a very useful
resource for the TuMP compilation for this category of hill.
The Welsh 200m P30 list
documents all hills in Wales that are at or above 200m in height and are below
300m in height, to qualify for the main list each hill requires a minimum of
30m of prominence.
The hills listed below are
updates to the Welsh 200m P30 list originally published on Geoff Crowder's
website. To see the original list click {here}
The original published list had
a Sub-List which was entitled ‘Hills to Survey’. This list consisted of all hills in Wales in
the stipulated height band that have a minimum of 20m of prominence, but do not
meet the minimum 30m of prominence to enter the main list, according to
Ordnance Survey map spot heights and contours.
Nowadays the standard Sub-List takes in all hills that have a minimum of
20m of prominence. However, the Hills to
Survey Sub-List discounted hills whose map spot heights gave a drop value of
less than 30m, but more than 20m. By doing
so, the only hills that were Sub-Listed were those that map values dictated
stood a chance of entering the main list, for example; if a hill had a summit
spot height of 250m and a bwlch spot height of 221m, it was not listed in the
Hills to Survey Sub-List as with 29m of drop I thought it did not stand a
chance of main list qualification.
When compiling the Sub-List I
was measuring many hills for P30 status using a basic levelling technique,
please click {here} for more information concerning this. I now know that Ordnance Survey spot heights
have a standard margin of uncertainty of + / - 3m associated with their
accuracy. Therefore many hills that were
not listed in the original Sub-List may have sufficient drop to enter the main
list. Because of this the Sub-List has
been altered to include all hills that have a minimum of 20m of drop but are
not known to attain the minimum 30m of drop to enter the main list.
The hills listed below are
those major amendments to the original Welsh 200m P30 list as it appears on
Geoff’s website. There are many hills
that have been promoted from the Hills to Survey Sub-List to the main list,
whilst there are many additions to the Sub-List now that it has been
standardised to include all 20m minimum but below 30m drop hills.
When the 200m P30 list was
first published it was the first to this category of hills and in some way it
and its other 100m height band lists paved the way for Clem’s data that later
appeared on the RHB file database and then for the TuMPs listing by Mark
Jackson.
As well as the first P30 list
to this height band the list is now the first to include a comprehensive
Sub-List.
TuMP baggers beware; as the
main list also includes P30’s not listed by Mark Jackson, so if you want to
visit all P30’s you’ll have to include some non TuMPs to do so.
The list will be updated on a
weekly basis and will be done so through each Group category, starting from the
north and working south. The second Group
that has major updates is Moel Hebog.
Moel
Hebog
North of Aberdesach at
SH 425 514 continuing north of the Afon Desach and east of the Afon Dwyfach
(centred on SH 453 485) to SH 478 372, west of the Afon Glaslyn at SH 582 380 /
Afon Colwyn to bwlch at SH 576 514, continuing to Llyn y Gadair (SH 568 521)
and the Afon Gwyrfai to Foryd Bay (SH 454 591).
Bordering with Yr Wyddfa to the north, Pen Llลทn
to the west and the Moelwynion to the east.
Twmpau - 200m updates
Moel
Isallt 286m SH 537 445
Another
hill that was always a prime candidate for promotion from the sub-list and with
the large scale Ordnance Survey mapping on the Geograph website giving a
252m spot height on the area of the bwlch it gives this hill 34m of drop.
Moelfryn 277m
SH 568 511
With a summit height of 277m
and bwlch contouring between c 240m – c 250m, with the hill to hill contouring
being relatively close when compared to the valley to valley contouring, this
hill was always a prime candidate for promotion from the sub-list and with an
estimated bwlch height of c 247m, it enters the list with c 30m of drop.
Sub-Twmpau - 200m updates
Bryn
Cwellyn c 272m SH 564 536
A forested summit near to Llyn-y-forwyn
which has an estimated summit height of c 272m (a separate point at SH 56454
53329 is estimated as c 271m) and an estimated height at Bwlch y Moch (SH 561
540) of c 252m, giving a drop of c 20m.
Craig
Isallt 233m SH 532 449
With a summit height of 233m
and an estimated bwlch height of c 213m, this hill just makes it in to the
sub-list with c 20m of drop.
Next update due on the 28st April 2014
No comments:
Post a Comment