What are Metric Mountains?
Of all the summit lists compiled so far, none have been truly metric in nature. Since all the OS maps are metric
now, it's impossible to work in feet anymore. Yet for some peculiar reason, presumably tradition, people still
persist in using imperial measurements. Certainly the numbers used these days are metric, but in every case I've
seen the author has chosen a logical number in the imperial system, such as 50ft, 100ft, 250ft, 500ft etc,
converted it to metric and simply rounded it off. Thus we have 15m, 30m, 75m and 150m. These numbers don't make
metric sense.
Of course all of these numbers are arbitrary and therefore ultimately meaningless anyway, but if we are going to
choose arbitrary numbers, isn't it about time we started choosing ones appropriate to the metric system?
The Metric System
The entire metric system is based on tens, that's the beauty of it. Apparently the length of one metre is
defined as being one ten millionth of the distance from the equator to the North Pole. That's a nice round number.
The length of Great Britain is approximately 1,000 kilometres, a tenth of the distance from the equator to the
North Pole. That puts things into perspective. This is what the National Grid is based on. The UK is divided up
into 100 kilometre squares, each with unique grid letters. Great Britain is ten of these squares long. Wales is
about two and a half of these squares long, therefore it's about one quarter of the length of Britain.
The maps themselves are overlain with a grid of squares, each of which is one square kilometre. One kilometre is
1000 metres. The height of Glyder Fawr is 999 metres, almost one kilometre, therefore it's scale height in relation
to the map is about the same as the width of one square. A 600 metre summit is six tenths of the width of one
square high. If you look at the height of any summit on the map, imagine it as a percentage of a grid square, you
can visually estimate the scale height of the summit. This is really very neat. Why anyone wants to bother with
feet in light of these facts I do not understand.
Logical Parameters
So what makes sense in the metric system? Well, there are two numbers which instantly spring to mind  1000
metres and 100 metres. The simplest, most logical (and still of course completely arbitrary) definition of a metric
mountain would therefore be any summit over 1000 metres with an ascent of at least 100 metres on each side. These
parameters would undoubtedly work well for Scotland, except that the tradition of the Munros is so firmly
entrenched that it seems unlikely that any new definition, however logical, could ever challenge the Munro's
domination.
In England and Wales on the other hand, these parameters are totally useless, yielding only three mountains in
Wales and none at all in England. To produce a useful list for Wales the numbers have to be reduced. The next most
logical number is 500 metres, which according to "Mountaincraft and Leadership" constitutes the distinction between
lowland and upland. Unfortunately, much of MidWales is a plateau which contains numerous insignificant 500 metre
"bumps", and many other 500 metre summits are of no great interest either. Like it or not, the traditional 2000ft
cutoff point eliminates most of these bumps and boring summits whilst preserving the more interesting ones, so
it's actually a rather good number.
2000ft is equal to 610 metres however, which is a really stupid number. It makes far more sense to use the
nearest metric equivalent of 600 metres. Using the parameters of 600 metres with a 100 metre ascent yields a useful
list of 72 Welsh summits, all of which are quite distinct and worthy of climbing. There are many other worthwhile
summits in Wales though, and few people would be happy about their exclusion, which brings me to another
interesting consideration.
Summit Categories
In most lists no distinction is made between summits, a summit is either included or excluded. In practice this
means that insignificant prominences assume as much importance in a list as do major summits, there's no way of
differentiating them in the list itself. Some lists do address this problem. Munro and Bridge each differentiated
mountains and tops and, more recently, Alan Dawson has done something similar with Marilyns and Hewitts (and also
introduced the concept of relative heights), although his distinctions of 150 metres and 30 metres are a little too
widely separated for my liking.
Going back to being metrically logical therefore, if a major summit is distinguished by having at least 100
metres of ascent on all sides, then the next degree of summit importance would surely be half of that, 50 metres.
Halving the number again produces 25 metres. I therefore propose to grade summits in three categories of
importance; A, B and C. Together they total 165 Welsh summits.
* Category A consists of major summits with a minimum ascent of 100 metres and over. These 72 summits are
undoubtedly the most worthwhile to climb and represent the best that Wales has to offer.
* Category B consists of secondary summits with a minimum ascent of between 50 and 99 metres. These 46
summits are quite distinct and many are well worth climbing in their own right.
* Category C consists of minor summits with a minimum ascent of between 25 and 49 metres. These 47 summits
often occur on ridges leading away from the more important summits, and tend not to be suitable as main objectives.
It would seem best to include them as part of a walk which takes in the more important summits.
Sources
These lists have been based primarily on the Hewitts list by Alan Dawson, who has been kind enough to give me
permission to use his data. I have been using the latest OS 1:25,000 and 1:50,000 maps to verify the existing data
and to fill in the gap between 600 and 610 metres. I have also included all of the summits from the latest updated
Nuttalls list since these seem to be quite popular. If anyone has any suggestions, comments or criticisms regarding
these lists please feel free to {email} me.
Alan Dawson can be emailed at alan@staclee.freeserve.co.uk}.
Full listings of Hewitts and Marilyns can be obtained from from {TACit Tables The Hewitts and Marilyns of Wales}.
Also check out the original Marilyns book {The Relative Hills of Britain}. The Nuttalls website is at
{http://www.nuttalls.com}.
