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 fourteenth
Group is the Tarennydd.
Tarennydd
North of Bae Aberdyfi
(Aberdovey Bay) at SN 592 945 and the Afon Dyfi (River Dovey) to SH 753 018,
continuing west of the Afon Dulas to SH 757 077 and the Afon Deri to bwlch at SH
737 093 and then west and south of stream to SH 724 102 and Llyn Mwyngil (Tal y
Llyn Lake), continuing south from SH 710 094 following the Afon Dysynni to Aber
Dysynni and the sea at SH 560 030.
Bordering with Cadair Idris to the north, Bryniau Dyfi to the east,
Pumlumon to the south and the sea to the west.
Sub-Twmpau - 200m updates
Foel
Fach c 277m SH 674 060
A slightly contentious entry to
the Sub list as it qualifies with an estimated drop of c 20m only because the
summit height has been estimated as c 277m.
Judgments of such kind are rather dubious, but the best estimate from
the size of the uppermost summit contour in relation to the other contours of
the hill is that the high point is approximately 7m above the 270m
contour. The bwlch contouring is between
c 250m – c 260m and has been estimated as c 257m at SH 673 058. The Ordnance Survey enlarged Geograph map has
three spot heights on the area of the bwlch, all of which have been assessed
and considered not to be at the critical bwlch, these are; 251m at SH 676 059,
256m at SH 674 058 and 257m (also on the OS 1:25,000 map) at SH 675 059.
Next update due on the 21st July 2014
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