Summer 2011 Part 7: Late August thunderstorms and a rare sunny morning at Glaslyn....


The Welsh Weather & Dyfi Valley landscapes Image-Library - Click

It's September 3rd and time to look back on the "official" Summer months of June-August. Summer 2011 has been noted for its cloudiness primarily, following the beautiful but worryingly dry Spring. I don't think it's been as bad here as some recent summers, but neither has it been brilliant - resulting in me dropping everything each time a sunny day came along, grabbing the fishing gear or walking stuff and getting out there!

Storminess has been reasonable though we have not seen any major Spanish Plumes that are a feature of the weather of NW Europe during most summers. Normally we get at least a couple with their stifling heat and humidity breaking down to incandescent night-time lightshows: not this year. Instead we have seen mostly short-lived thundery showers coming in on the Atlantic-dominated airflow, the latest of which rewarded a locally-based intercept on August 25th. I don't tend to go more than ten miles from home these days as a rule owing to the cost of travel - my annual mileage is decreasing by over 10% a year - it's about being selective and better organised. So if I go to the coast I'll take containers to fill with washed-up seaweed for the compost-heap and boxes to carry any mushrooms, samphire etc that I might come across on my wanderings. Killing two (or three) birds with one stone has become the norm now.

On the morning of the 25th the rainfall radar indicated storms moving up on the southerly steering-flow, but on arrival at my normal vantage-point at Borth they were falling apart, so I headed to Ynyslas to get some new images for the Library. This one - looking across the Leri outfall and up the Dyfi Estuary at low tide - was a pleasing result.....

Looking up the Dyfi Estuary from Ynyslas was this one looking straight across to Aberdyfi with the disintegrating storm visible to the L:

Aberdyfi from Ynyslas

Here's a zoom-out - it was still chucking out a fair bit of rain but lacked any interesting structure.....

Heavy shower just offshore, Ynyslas

That afternoon, more intense cells showed up across South Wales on the radar and became electrified. I watched them drift northwards and a couple of hours later popped down to Aberdyfi for a second intercept. This cell and the obviously very heavy rain was heading straight at me, although the visitors on the beach seemed unaware of what was about to happen!

Thunderstorm approaching Aberdyfi

A bright flash of lightning over the opposite side of the Estuary and, a few seconds later, loud booming thunder got them moving. The road quickly became jam-packed as the ensuing mass-retreat became a rout. I found a space with a view out over the Estuary and decided to stay put and enjoy a bit of natural violence.....

Thunderstorm in progress, Aberdyfi

This is the last shot I took - within moments the rain was too heavy to risk exposing the camera to it. Another bright flash of lightning gave forth a simultaneous thundercrack: the rain now fell so heavily that the thunder generated by the next flash - again overhead - was, despite arriving in just a second, barely audible. This was fun!

Ten minutes later and the heavy, electrified core of the storm had moved on up over the hills behind Aberdyfi. The traffic had cleared a bit so I moved on - encountering floodwater near the entrance to the Aberdyfi Outward Bound centre....

Flooding after the thunderstorm near Aberdyfi

The storm was clearing right away by the time I reached Frongoch Boatyard, with the thunder now as faint booms echoing from the high ridge of the Tarennau. A typical, small Atlantic airflow storm: these are always better in the Autumn and Winter months, when cooler air moving over warm sea water leads to a much greater degree of instability: something to look forward to for the coming months!

The storm clears - Frongoch Boatyard

Cloudiness dominated the final days of August until the 31st, when an early morning hole appeared in the cloud - and all of Mid-Wales found itself under clear skies once the night-time valley-mist had burnt off. Seizing this unexpected opportunity I headed up into the hills for a morning's walking and photography. I picked the Glaslyn area as I knew it would be at its best with the acres of heather in flower. Bands of cumulus cloud started to develop from low-level capped convection, creating dappled lighting - much better than completely clear blue sky which, to the photographer, can be difficult to work with. Here's a view of Glaslyn, with Moel Fadian to the R and the peaks of Cadair Idris and the Dyfi Forest forming the backdrop, on the other side of the Dyfi Valley......


Glaslyn is a small, shallow lake situated in an equally shallow depression in the acidic moorland of the area. It, and its surroundings, are managed as a nature reserve by the Montgomery Wildlife Trust. It was amazing to find the lake in almost windless conditions.....


The acidic conditions mean that there are very low nutrient levels in the water - not a lot lives in the lake as a consequence. The bed of the lake is paved with fragments of Silurian shale, coated with oxides of iron and manganese. The rare plant, Quillwort, is one of the few things that manages to thrive in these unusual conditions.


Around the shores of the lake, heather-moorland leads down to damper ground, with vivid green patches of sphagnum-moss, dotted with sedges and rushes and, here and there, the bright red insectivorous Sundew - a beautiful plant that is surprisingly tricky to photograph well - often it is hidden by sedge-blades. This more isolated but vigorous patch gave a reasonable result.....

Sundews, Glaslyn

The heather-moorland is dominated by the Common Heather (or Ling), but the Bell- and Cross-Leaved species are also common. At this time of year the colours are fantastic - every shade of pink and the occasional clump of white heather:

White heather, Glaslyn

White Common Heather - Calluna vulgaris var. alba - is a familiar sight to anyone who walks these hills in August: I was more surprised to find this white Cross-leaved Heath:

White bell-heather

A boggy but level footpath winds pleasantly around the shore of the lake, but this detour is an absolute must unless the weather is especially vile. I loved the way the lichen has started to cover over the sign!

Path to the Edge, Glaslyn

This is the viewpoint - showing why it is worth the effort to reach it (which isn't much). Here, the northern part of the uplands that form the Plynlimon massif suddenly come to an abrupt end: slopes fall away steeply to the valleys below in a 350m high escarpment-like feature. Looking out from the end of the path, almost the entire Dyfi catchment can be seen, from Cardigan Bay to the western slopes of the Arans (a move a few hundred metres west will give a full view of them). The Tarrenau, Cadair Idris and the Dyfi Forest form the rest of the backdrop - an inspirational place to tarry awhile on a calm day such as the one I was blessed with....

Path to the Edge, Glaslyn

Here's the view west out to Esgair Foel-y-llyn:

Foel Esgair y Llyn

To the east, Moel Fadian dominates things, with, in between, the great ravine of Esgairfochnant:

Moel Fadian and the Ravine

I've had a long familiarity with this feature - more about that below - but had not previously investigated it from this side. Slipping and sliding carefully down a heathery gully, I found myself on 45-degree scree which I rattled down for a few tens of metres before traversing off left above some shattered crags. Here, the ground flattened a little before dropping again precipitously to the valley floor. The light was perfect......

View north from the upper slopes of the Ravine

Looking back up the ravine from this lofty vantage-point, only a part of it could be seen, but what a sight!

View east from the upper slopes of the Ravine

Descending into the Ravine

Now to the familiarity bit. During a long dry summer many years ago - 1995 I think it may have been - my mate Peter Jones from Newtown and I decided to take a look at the old copper-mine at the foot of the ravine's headwall. The mine was interesting but small, but now that we were down there, what about descending the ravine itself?

We returned several times, with much rope and some "shale pitons" that Peter had made by welding brackets to old front-end loader tines. There is no other way of fixing belays on this ground. The whole place is so loose that coming back up is much easier if you have a jumar on a fixed rope to hang onto as the ground gives way before your feet.

This shot is looking up the entrance/exit gully, about 150m long and consisting of scree overlying disintegrating slabs of shale. Below the mine there are several short rock-steps that are easier and safer to abseil owing to the totally loose rock, with long sections of steep scree in between.

Over several trips we made our way down and down this remarkable place. In the end, we simply ran out of ropes to fix!

The ravine from our furthest-down point
This shot was taken close to our lowest point, looking back up towards the headwalls. You can only truly appreciate the sheer scale of this place by making your way down alongside the stream - the juvenile Afon Dulas. The ravine at this point is over 300m deep.

The "shale-pitons" may well still be there - it would take a strong man to carry them back out! To fix all the pitches you would need at least 250m of rope, plus an unknown amount for the pitches that lay beyond our lowest point. I guess the whole thing could be scrambled, but the consequences of a slip on this steep and disintegrating ground would be serious and getting someone out of here with a broken leg would be a challenge, to put it mildly! I wouldn't do it without ropes, and would not advise anyone else to, either,

This photograph was published in the climbing magazine, "High", to accompany an article I wrote about this place - unique in Mid-Wales. One could be forgiven for thinking that it was somewhere in the Mediterranean!

The lack of vegetation on these steep lower slopes is due to a) their constantly mobile nature and b) perhaps the very acidic conditions - the rock is the Cwmere Formation, a mudstone rich in the iron sulphide, pyrit
e - which weathers to produce sulphuric acid.

I can't help thinking that the complete traverse of the ravine, going up, would make a great winter climb in the right conditions - very heavy prolonged frost without too much snow on the steep, avalanche-prone slopes above. The summer dangers of disintegrating rock would then be much diminished. One could simply follow the stream. The annotated aerial pic below shows the layout of the place relative to the images above.

Esgairfochnant Ravine aerial topo

Adventures in the depths of ravines aside, pick a clear, still morning and head out along the shoreline of Glaslyn, the air humming with bees busy amongst the heather-blooms. Turn up past the lichen-encrusted signpost, climb the gentle slope and descend slightly to where the path ends with nothing beyond but clean air and the green fields and woodlands of the Dyfi Valley, with further ranges of mountains in the distance. It is one of those places that truly deserves the adjective, "special".

The Welsh Weather & Dyfi Valley landscapes Image-Library - Click HERE