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 fourth
Group is the Moelwynion.
Moelwynion
North of the Afon Dwyryd from Traeth
Bach at SH 592 362 and the Afon Cynfal to SH 760 432, continuing north of the
Afon Conwy to SH 856 511 and then south of the Afon Conwy to SH 798 573 and
south of the Afon Llugwy to Llynnau Mymbyr at SH 705 572, continuing south of
the Nant Gwryd to Llyn Pen y Gwryd and SH 660 556, east of the Nant Cynnyd to
the Afon Glaslyn and Llyn Gwynant at SH 644 519, continuing east of the Afon
Glaslyn to Llyn Dinas at SH 616 495 and to the sea at SH 582 380. Bordering with the Rhinogydd to the south,
the Arennig to the east, Mynydd Hiraethog, Carneddau and Glyderau to the north,
and Yr Wyddfa and Moel Hebog to the west.
Twmpau - 200m updates
Cefn
Bychan c 244m SH 695 454
The uppermost ring contour on current
maps is c 240m with the bwlch positioned at an estimated SH 698 458. Bwlch contouring on current maps is between c
210m – c 220m and suggests a height of c 212m – c 213m. The Ordnance Survey Historical 1:25,000
map on the Sabre Maps website gives an uppermost contour of 800ft (243.8m) and
a lowest continuous contour encircling the hill of 700ft (213.4m). This lower contour is dotted implying the
area has been extensively altered.
Current maps imply the critical bwlch to be at the junction of Towyn
Road and Dorvil Road in Blaenau Ffestiniog.
The Ordnance Survey 1:2500 map from 1977 on the Old Maps website gives a
levelled height of 212.1m positioned at this road junction. The best available evidence suggests
the height of Cefn Bychan is c 244m and its bwlch is 212m, giving c 32m of
drop.
Sub-Twmpau - 200m updates
Pt.
294m 294m SH 727 533
With a summit spot height of
294m and a bwlch spot height of 268m, this hill has 26m of drop.
Pt.
248m 248m SH 671 424
This hill has a height of 248m
on the large scale Ordnance Survey mapping
on the Geograph website and it has two options for its critical
bwlch, they are positioned at SH 667 424 and SH 673 425, both are estimated to
be c 223m, giving this hill c 25m of drop.
Pt.
c 281m c 281m SH 776 549
Another forested summit with
both summit and bwlch height being estimated from contour interpolation, with
the bwlch estimated as c 259m at SH 775 550, giving this hill c 22m of drop.
Y
Foel 288m SH 799 503
The bwlch is positioned between
c 260m – c 270m contours and is estimated as c 267m at SH 802 503. This gives the hill c 21m of drop.
Pt.
257m 257m SH 785 556
There are two options for this
hill’s critical bwlch, they are positioned at SH 785 553 and SH 787 551, both
are estimated to be c 236m, giving this hill c 21m of drop.
Pt.
c 274m c 274m SH 696 518
Another forested summit with
both summit and bwlch height being estimated from contour interpolation, with
the bwlch estimated as c 254m at SH 695 519, giving this hill c 20m of drop.
Clogwyn
Mawr 269m SH 699 519
Looks like a good rocky summit
clear of forest, although the majority of the hill is within conifer
plantation. The bwlch is positioned at
SH 697 518 and has been estimated as c 249m, giving c 20m of drop.
Pt.
263m 263m SH 626 484
With a height of 263m on the large scale Ordnance Survey mapping
on the Geograph website and an estimated bwlch height of c 243m which is
positioned at SH 625 484, this hill has c 20m of drop. The same enlarged mapping gives a 241m spot
height on the area of the bwlch at SH 625 485, although this may be the
position and height of the critical bwlch, contouring suggests otherwise.
Pt.
256m c 256m SH 784 549
A forested summit near to Llyn
Elsi which has a height of 256m on the large
scale Ordnance Survey mapping on the Geograph website, the bwlch is positioned
at SH 787 551 and is estimated as c 236m, giving c 20m of drop.
Pt.
229m 229m SH 621 459
With a height of 229m on the large scale Ordnance Survey mapping
on the Geograph website and a bwlch positioned at SH 621 459 with an estimated
height of c 209m, this hill has c 20m of drop.
Next update due on the 12th May 2014
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