Postcard from Fan y Big

The welshman who went up a mountain and came down a hill

When is a mountain no longer a mountain? When it becomes a hill. Sound strange? Read on.

A mountain is a large land form that stretches above the surrounding land in a limited area, usually in the form of a peak. A mountain is generally steeper than a hill. Mountains are formed through tectonic forces or volcanism. These forces can locally raise the surface of the earth. Mountains erode slowly through the action of rivers, weather conditions, and glaciers. A few mountains are isolated summits, but most occur in huge mountain ranges.

Jonathon Davies, Going Postal
Path ascending towards the Beacons

There is no universally accepted definition of a mountain. Elevation, volume, relief, steepness, spacing and continuity have been used as criteria for defining a mountain. In the Oxford English Dictionary a mountain is defined as “a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which, relatively to the adjacent elevation, is impressive or notable.”

Jonathon Davies, Going Postal
One of several waterfalls

The UN Environmental Programme’s definition of “mountainous environment” includes any of the following:

  • Elevation of at least 2,500 m (8,200 ft);
  • Elevation of at least 1,500 m (4,900 ft), with a slope greater than 2 degrees;
  • Elevation of at least 1,000 m (3,300 ft), with a slope greater than 5 degrees;
  • Elevation of at least 300 m (980 ft), with a 300 m (980 ft) elevation range within 7 km (4.3 mi).

In the United Kingdom and the Irish Republic, a mountain is usually defined as any summit at least 2,000 feet (or 610 metres) high. whilst the official United Kingdom government’s definition of a mountain, for the purposes of access, is a summit of 600 metres or higher. In addition, some definitions also include a topographical prominence requirement, typically 100 or 500 feet (30 or 152 m). For a while, the US defined a mountain as being 1,000 feet (300 m) or taller. Any similar landform lower than this height was considered a hill. However, today, the United States Geological Survey (USGS) concludes that these terms do not have technical definitions in the US.


Jonathon Davies, Going Postal
Deep valley sloping up towards Fan y Big

Fan y Big is a subsidiary summit of Waun Rydd in the Brecon Beacons National Park, in southern Powys, Wales. At 2359 feet or 719m, Fan y Big lies at the western tip of the Gwaun Cerrig Llwydion plateau. Its name translates as ‘peak of the bill’ – perhaps in allusion to its striking pointed shape, as seen from some directions. The summit is bare but marked by a cairn, which stands on the edge of its precipitous western face.

Jonathon Davies, Going Postal
A slippery path

The peak is prominent on the north facing escarpment of the central part of the Brecon Beacons and several footpaths cross the summit. All the surrounding land is open access and so open to all. In poor weather however, the paths are the safest route for access. The peak is often crossed by hikers aiming for Cribyn (mountain), Pen y Fan and Corn Du, and also forms part of the Fan dance.

Jonathon Davies, Going Postal
I went the wrong way at one point, but it did yield a spectacular view

In common with other peaks of the Brecon Beacons, the upper slopes of Fan Big are formed from sandstones of the Brownstones Formation of the Old Red Sandstone laid down during the Devonian period. The lower slopes of the hill are formed from sandstones and mudstones of the underlying Senni Beds Formation. The rock strata tilt gently southwards. The valleys to the northwest and east nurtured small glaciers during the last ice age. This glacial erosion resulted in the very steep northern face which the mountain possesses.


Jonathon Davies, Going Postal
At the summit

Recently Fan y Big has been reclassified from a mountain to a hill (Fan not so Big). The mountain, sorry hill, summit was 2,359ft which is above the required height for a mountain. However, a mountain peak must have a drop between the nearest summit of at least 98.4ft, or 30m. Using new-fangled technology, Myrddyn Phillips from Welshpool, measured the mountain.

The technology is said to be highly accurate, using hundreds of readings and data points. It found that the peak of Fan y Big was 2351 ft, shorter than previously thought, and the drop to the nearest peak was 93.4ft. This meant that under the strict UK system it had to be removed from the list of mountains.

Well, after hearing all that I had to walk up it, didn’t I? After all, it’s only a hill.

Jonathon Davies, Going Postal
There are many windswept valleys on the way

For the first part of the walk I followed part of the route of the “Fan Dance,” which some of the ex-servicemen on the blog may be able to tell you more about. The real thing covers 15 miles with a time limit of four hours. I did 8 miles in three hours, this includes drinks breaks, lunch, rests, etc. This was by far the toughest walk I have undertaken, and I am an experienced walker and regular in the gym. I only did part of the course and yes, it really is that difficult, and I can see why people die when attempting it.

Jonathon Davies, Going Postal

I followed the route up from Torpantau train station, ascended for a couple of miles, then deviated and went across to Fan y Big. I then took a different route back, which enabled me to take in more of the scenery. It may technically be a hill, but it is certainly a testing climb.

Jonathon Davies, Going Postal
At the summit looking towards Pen y Fan

Lush greenery and trees at the lower levels gives way to the more typical and recognisable beacons scrub as you climb higher. There are stunning views all along the walk. It will come as no surprise that it is completely unenriched. There are various different peaks and different valleys. These are often known as a cwm. It was here glaciers formed during the ice age, then spread out carving away huge chunks of the landscape. A key feature that lets you know if a valley once had a glacier is the large width compared to the river size.

Jonathon Davies, Going Postal
From left to right: Pen y Fan, The Cribyn and Fan y Big

Waterfalls and streams abound, even higher up. It is windy at the top, even in good weather. From most places the distinctive twin peaks of Pen Y Fan loom over the horizon. You can see hawks on the wing if you are lucky. Sheep and some horses can be seen clinging to the steep mountain and hillsides. You can also get good views of the Pontsticill and Upper Neuadd reservoirs. I would recommend this route for experienced walkers, taking plenty of water. Tough but rewarding.

© Jonathon Davies 2018

Audio file