An autumnal small leaved lime and upland oak wood

A weather forecast for the Brecon Beacons National Park stated fog/mist/low cloud, light rain and negligible wind, so it was with high hopes that I set off for Coed y Rhaiadr, there was fog, negligible wind and light drizzle all the way there until I dropped down to Hirwaun. Where there was no fog, mist or rain and the rotating blades of wind farm turbines indicated wind too. Still there are plenty of options in Coed y Rhaiadr with autumnal colour and I headed for an area of woodland high up the ravine slopes with photogenic veteran oaks. Passing the waterfalls the area is noted for indicated the the tree canopy that provide a backdrop had been stripped of leaves from the recent passage of Storm Ophelia. The oaks I had hoped to photograph were also denuded of leaves, so it was back down to the river.

The numerous waterfalls make it a magnet for photography workshops in the autumn and it hadn't taken long for the workshop providers and punters to stake out their claims. I didn't see anyone photographing the woodland sans waterfalls, which is a pity as the woodland is designated as a Special Area of Conservation. A riparian small leaved lime in autumnal colour provided the necessary inspiration and a native woodland tree that I've rarely found a) in autumn colour and b) suitably sited to make a photograph. From the chosen viewpoint the rain serendipitously broke up the river surface, mitigating the sky reflection. Whilst waiting for the wind to ease I watched a Dipper working its way downstream, diving and feeding from the riverbed. The wind eventually died down to make a photograph and the only audible sound was rain falling and dripping down through the canopy.

Another storm was forecast in a few days time so I made the decision to maximise my photography opportunities and cut short my excursion in Coed y Rhaiadr to visit a nearby upland wood that should have been relatively sheltered from the Storm Ophelia's winds. Some parts of the wood have a closed canopy whilst other parts are more open in nature and mature sessile oaks are spread along a steep sided valley, with crowns and branches shaped by the elements. A few oaks have layered their branches which are mantled with epiphytic lichens and well within tripod height.

Birch, alder, willow, holly, hazel, hawthorn, ash and rowan trees make up the rest of the woodland trees and with more time I would have photographed these, but the oaks were concentrated on for this visit. I do not know anything of the woodlands history, many of the oaks are pollarded and the hazel trees are coppice stools, hinting at a past management regime. The wood is not officially designated as ancient woodland, but is depicted on first edition 19th Century Ordnance Survey maps and some of the oaks appear to be of some age. The lack of regeneration indicates the woodland is overgrazed and has been so for many years.

Eventually the wind and driving rain brought an end to the excursion and a note made to revisit again in the future.

Elenydd trip report

An afternoon trip to mid Wales and the Elenydd. It was evident during the journey that extensive cloud cover determined that a walk in the Oak woods would be more productive than up on the hills. I was also curious to see how an area of woodland designated as Special Area of Conservation was being managed.

A wander along a stream led to a waterfall, where the combination of inclined cleavage, bedding planes and joints in the bedrock, contributed to a staircase of waterfalls. I thought this would have some potential later in the year with autumnal foliage and higher water flows.

It was heartening to see that the oak woods were naturally regenerating with oak, birch, holly and rowan trees in the form of saplings and seedlings. No plastic tubes were evident, so reduced levels of herbivore grazing were most likely the trigger for regeneration.

The woodland management also extended to leaving standing and fallen deadwood, increasing the biodiversity and rebalancing the woodlands naturalness. The trip was a good one, some stuff to ponder and to a laymans eyes the woodland was recovering.

A trip to photograph an ancient weakness in the earths surface

My interest in the science of geology is its endeavour to unravel the history of the earth from rocks and structures, a complex story that requires the mind to grapple with the depth and enormity of geological time and processes. It is also personally rewarding to make a landscape photograph that conveys the geological story of a landscape.

From: Carney, J.N., Horak, J.M., Pharaoh, T.C., Gibbons, W., Wilson, D., Barclay, W.J., Bevins, R.E., Cope, J.C.W. & Ford, T.D., (2000), Precambrian Rocks of England and Wales, Geological Conservation Review Series, No. 20, Joint Nature Conservation Committee, 

At some point in the deep geological time of the Precambrian, the Cymru and Wrekin terranes collided and the collision zone (suture) or terrane boundary, has created an inherent weakness in the earths crust and a nucleation point for subsequent dislocations from external tectonic forces. Geological mapping has revealed that the Cymru/Wrekin terrane boundary has a long history of movement in the Precambrian, during the Caledonian Orogeny and then the Variscan Orogeny. These movements along the terrane boundary generate faults and folds (disturbances) in the overlying rocks and these features have been exploited by erosional processes, notably the actions of freeze-thaw weathering, flowing water and glacial ice. Which is a good thing, as the scenery of the Brecon Beacons National Park would be otherwise a lot photogenically poorer.

Faults of the Fforest Fawr Geopark
http://www.fforestfawrgeopark.org.uk/understanding/rocks-and-geology-of-the-geopark/faults-and-folds/geological-faults-in-the-geopark/

The head of the Senni valley has; a classic glaciated cirque; a U shaped profile; a miss fit water course of the Blaen Senni and the upper valley is aligned with the Tawe (Swansea) Valley/Cribarth disturbance. The valley orientation is initially NE before abruptly swinging north, which coincidentally aligns with another major structural trend which is termed Malvernoid. To the east of where the Senni valley swings north is the Cwm-du valley, a hanging valley above the floor of the Senni valley, with a suite of moraines and steep headwall of Graig Cwm-du. Cwm-du also has a mis fit stream and coincidentally the head waters of the Nant Cwm-du also parallel the Tawe Valley disturbance. This is an area I've visited on numerous occasions to try and make an image that I'm happy with.

There are a number of approaches to reach the vantage point on the Fan Frynych ridge over the Senni valley, the most scenic approach being through the Craig Cerrig Gleisiad National Nature Reserve and at this time of year, there is the potential for low angled sunlight on the northerly facing scarps and valley sides, with patches of heather in bloom for floral interest.

The weather forecast
Credit - Met Office

The forecast was optimistic considering the picture of the visible satellite, rainfall radar and wind strength readings from online weather station, nonetheless there was potential for some atmospheric lighting.

The scenic Craig Cerrig gleisiad
Foreground - vegetated antiscarps of the landslide and western headwall
Middle  - Craig cerrig-gleisiad
Horizon left - Cadair Arthur and shower cloud

Surveying the landscape to the south west from Fan Frynych's summit and it doesn't take much imagination to visualise a continuous plateau surface to Fan Llia, before erosion processes exploited  weaknesses in the bedrock and the dissection of the plateau. Sadly on this trip, as with previous trips the weather dictated the view of the Senni Valley would again remain unphotographed, this time the winds strength was problematic, maybe next time?

Undulating plateau dissected by Cwm-du

Cwm-du and the north facing scarp of Craig Cwm-du with layer cake stratigraphy of the Lower Old Red Devonian Senni beds

Instead a tactical retreat was made to a headwater stream of the Nant Cwm-du, with a view down into the Cwm-du and Senni valleys and 'relative' shelter from the wind. A patient wait for a break in the shower clouds, was spent donning and doffing rain wear and pondering plateau glaciation, cold based ice, periglacial processes, the thickness of soliflucted till, oh and the delights of descending through the landslide debris of Craig Cerrig Glesiad in head torch light ...

My patience was rewarded with a fortuitous break in the clouds. It wasn't the landscape image I had hoped for, but a satisfying one with the atmospheric lighting and a view along and down an ancient weakness in the earths crust revealed by erosion processes.

Plan A, oh yes indeedee

The UK was gripped for a few days in an 'Arctic blast', the Mountain Weather forecast noted snow falling, less endearing were the words upland gales and wind chill in minus double digits. I thought it best to wait for the wind to ease and finally initiate Plan A.

A 20 second exposure

When the forecast finally predicted that winds would drop, Plan A was finally rolled out. Parking up at Blaen-y-glyn car park and there was a lot of cloud overhead, maybe it would break up?  Ice was conspicuous, but there wasn't as much snow as I'd been expecting and not full on winter conditions. I appreciate the effectiveness of crampons, but the convenience of Kahtoola micro spikes generally wins out for the Brecon Beacons terrain, the crampons were left in the boot. The path up had some interest in parts with sheet ice, consolidated snow and thigh deep drifts, the going was good though, courtesy of walkers who had trail breaked on the preceding days. Up on the plateau a few things became apparent.

Caerfanell valley

Extensive hill fog covered the Brecon Fans and higher ground, which was disappointing, as these summits were to form the main composition viewpoint. The northerly wind was also a lot stronger and buffeting, this was bad for both windchill and tripod stability. Conversely, the northerly wind was a good thing too, as cold, clear, moving air offers excellent visibility and clarity, not something that can be typed too often, as the UK has a maritime climate with moisture laden air. The cloud overhead was extensive, but the south easterly horizon appeared clear. There seemed little point in heading off to be enveloped in fog and plenty of time to spare before dawn to revise my plan and find a viewpoint. The chances of side lighting were minimal, a pity as the landslide under Cwar y Gigfran might have had some potential,  a view of the sunrise down the Caerfanel valley offered the best hope, with the misfit streams in a glaciated valley.  I dumped the rucksack and spent 30 mins scouting the edge of Craig y Fan Ddu for i) a sheltered viewpoint and ii)  I needed to keep moving to keep warm.

I was fortunate enough to get a red sky and horizon for dawn and sunrise, less fortunate was the wind strength and buffeting, which made most long exposures soft and forced a move to the sheltered ground around Blaen Caerfanell.

With sunrise over,  I decided to cut across Gwaun Cerrig Llwydion to the Craig Cwareli overlooking Cwm Oergwm, the aptly named cold valley. Gwaun Cerrig Llwydion is a plateau. in part covered with an eroded and eroding surface of blanket peat and as the ground was frozen solid, the joys of shin deep bog were negated. In any case the snow mantled peat hags would offer some interest, whilst waiting for improved weather to hopefully manifest itself.  Wind ablation of snow created this mildly unnerving scene amongst the peat hags, anthropogenic snow heads with grass for hair.

Snow heads

The mechanism(s) for blanket peat erosion, forming peat hags, hasn't convincingly been proven, but  whatever the cause, the peat hags on Gwaun Cerrig Llwydion are impressive in their size, number and extent. I also managed to disturb some the resident Red Grouse on my wander.

Brief sunlight

Before everything had froze solid, water draining from the blanket peat had formed icicles and the weight of ice hanging had visibly stretched and pulled down on the vegetated layer covering the peat. Once this protective vegetation mat is removed, the underlying peat is exposed to the elements and weathered away. From my limited observations, icicles indicating water draining from blanket peat usually appeared in the 'head wall' of an erosion embayment, cutting back into the blanket peat.

Icicles

With the sun showing signs of breaking through the cloud and Cribyn's summit clearing of hill fog, it was heads up and time to explore the views.

 The cloud masking Cadair Arthur refused to play ball and clear, sigh.

Cwm Oergwm

Craig Cwareli was fully exposed to the wind, the windchill was pretty severe and I was thankful to Canon engineers for designing a camera that I could operate wearing gloves.  At the head of Cwm Oergwm there's a suite of landforms at the foot of the escarpment that have proved elusive for me to photograph, I was hopeful that snow cover and a BW conversion would reveal their nature, with the benefit of hindsight, I probably needed a better point of view, perspective and more snow. Some of the landform features represent cirque glaciation moraines, other landforms are more contentious and have provoked some discussion on their nature.

100mm BW

After 6 hours on the hill, the ominous darkening of the sky and lowering of cloud base, signalled an end to day and time to head home. Plan A had at last been rolled out, but I'd have liked the hills to have cleared of fog/cloud for dawn and try again to get the views I'd last seen in 2013. On the other hand I'd probably have missed the views over the Caerfanell valley.

2013 Dawn

2013 Sunrise

Snow, yay!

The UK winter of 13/14 was the wettest since records began and snow events were at a premium, so it was with some anticipation with snow falling, that I made plans for a dawn excursion. Snow cover has the ability to reduce the visual complexity of a landscape, by blanketing vegetation and reveal land forms. So, great plans were made, winds were at an acceptable strength for longish exposures and I even allowed an extra 10 mins for clearing the car of snow in the morning. Sadly, the plan slowly unravelled during the journey. The majority of UK drivers seem content to carry on with normal tyres and mitigate the hazards of snow/ice by travelling at crawling speeds until gritted or snow/ice free roads are reached. If conditions get too bad, they simply abandon their car, which really adds to the congestion misery. Whilst slowly crawling along behind a dispiritingly long line of tail lights, I reflected on the aforementioned and that whilst my investment in winter tyres is a sensible move, I really should have set the alarm for 1 hour earlier when snow fell overnight and as the extended travel time, ate into the walk time, Dawn at Great Plan A was scuppered and others too, eventually a trip up to the oh so familiar enivrons of the Black Mountains southern flank was settled on.

Cumulonimbus Incus

The walk up was initially over a dusting of snow, until the Ffridd wall was reached and then the snow depth increased to several inches. Where the 'mountain wall' has been sited in empathy with the upland environs and not with a surveying line, I have noticed the 'mountain wall' often seems to demarcate fairly accurately the zone of snow accumulation.

Onwards and upwards and with views opening up, a band of cloud was present to the south extending across the horizon from the SW to SE, sigh. so no alpen glow or warm red light. It was very much a case of waiting for something to happen towards sunrise. A cumulonimbus incus cloud offered some interest and if the cloud had arrived 30 mins later there would have been some very nice lighting.

Instead there was the opportunity to experiment with the camera white balance (WB) settings, as sometimes manual settings have produced a more pleasing image colour than the camera auto WB. Conventional wisdom says WB can adjusted in RAW post processing, I think it is probably best to get it thereabouts in the field and it is something I'm still experimenting with, a better memory would help too.

A belated sunrise

The effect of snow and low angled light reduces the complexity of a landscape and highlighting landforms was  illustrated by the view across the Usk valley to Craig y Cilau on Mynnyd Llangatwg where the landslide scar/glacial cirque were revealed.

Craig y Cilau and Mynydd Llangatwg plateau

One landform that I'd seen on previous trips was a lobe or debris tongue, with depression and debris ridges. The snow cover highlighted the form and nature, with the intriguing possibility of a rock glacier origin, or alternatively winnowed landslide debris. The south facing aspect of the slope and the gradient are potential settings for ice cored debris flows that form in severely cold climates.

Boulder lobe from a rock glacier or winnowed landslide debris?

Spin drift rising from exposed ground was a visible indicator of the wind strength increasing, sadly my efforts to capture spin drift failed miserably. With cloud sheets approaching from the west and thunder snow forecast it was time to head back to the car, whilst the weather was still good and photograph the Ffridd wall and trees mantled in snow. An enjoyable trip and always a childish pleasure to walk on virgin snow that's not too deep.

Stock pen and Ffridd wall

Field beech and graze line

Winter light and colour

This post covers two excursions to the Brecon Beacons National Park and locations avoiding the high winds and gusts to gale force intensity, the sheltered lee side of scarps/hill sides.

The first trip was an afternoon excursion to the eastern flank of Y Mynydd Du, to coincide with the departure of a weather front and the relative shelter of the Old Red Sandstone escarpment. Anomalously high Autumn temperatures - well into winter and grass was still holding a green tinge of growth - and an absence of frosts, hadn't brought the rich palette of colour to the upland sedges and grasses, the cold spell over the festive season might have rectified this.  This area also encapsulates the headwaters of the Afon Tawe and the lake Llyn y Fan Fawr, it is fair to suggest there's no shortage of moisture and recent heavy rainfall had left the ground saturated with surface water streaming down the hill, streams in torrential flow and below ground the natural soil pipes were revealed with water flowing into normally dry gulleys.

The moorland also has a number of eroding peat hags, an increasing UK wide phenomena that is causing some debate as to the cause, in environmental and earth science circles

Eroding Peat hag

The erosion of preat hags does reveal a ground surface covered in rock debris, much of it angular in nature and probably a relict land surface from the the end of the last glacial stadial 11,500+ years BP when this area would have resembled arctic tundra.

Rock debris revealed by eroding Peat.

On the theme of controversy and Ice age landforms, Llyn y Fan Fawr has prompted some discussion of its origin, an active glacier is the popular consensus, there are alternative views though.

View to Llyn Y Fan Fawr and present outlet stream (not visible)

I can't find any references, but the moorland does seem to have a suite of landforms arraigned normal to the down valley glacier ice flow.

There's also a scatter of erratics, that might be from winnowed moraine or till and on the western flank of Fan Gyhirych a series of lineations that are discordant to the southerly dipping bedrock, these have been postulated as glacial lineations.

Fan Gyhirych glacial(?) lineations

With the wind easing, I ventured up onto the escarpment for a look around. On the way up, the path  exposed these mudstone, siltstone and sandstone beds, that nicely sum up the composition of the Brownstones formation.

Sandstone, siltone and mudstone beds, of the Old Red Devonian, Brownstones formation.

The wind was still on the strong side, so only Fan Hir was visited for a view over to Fforest Fawr and with ominous cloud rolling in from the west it was back to the car.

View from Fan Hir

On the way down, a stop to record the infant Afon Tawe flowing through soliflucted sheets of glacial till.

Infant Afon Tawe

The 2nd trip was an afternoon excursion too, the morning wasn't the best and the Mountain Weather Forecast hinted strongly that even with a weather front clearing, walking at elevated and exposed routes would be challenging, so keeping the tripod steady seemed optimistic for dusk, more interesting was the forecast of sunshine and snow showers.  The car parks for popular low level walks would be full, so the National Nature Reserve of Craig Cerrig Gleisiad and Fan Frynach, seemed the best bet for quiet and some views. The National Nature reserve has a lot to offer from a geomorphology and flora perspective, I'll hope to cover these aspects in future posts/visits, as the images on this trip were of the views. I'll add that the Mountain weather forecast was spot on.

Cadair Arthur

I've always known the peaks of Corn Du and Pen y Fan as Cadair Arthur, but this name seems to have fallen from favour in recent times. A pity, as viewed from the NE the twin summits do appear arm chair like, the connection with Arthur I have no idea, but there's a thread of Arthurian folklore in the Brecon Beacons NP.

Breaks in the cloud were few and the showers were light in intensity, the final image, just caught some light before the sun dropped below the hills.

The National Nature Reserve makes for an interesting outing with plenty to see and varied routes at high and low levels.

Plan C and a fallible technique

My better 1/2 decided that she too would accompany me on a dawn foray! What precipitated this outbreak of female enthusiasm, was the weather forecast which promised - light winds, temperature inversion, frost, valley fog/mist patches, sunshine etc, with the proviso of cloud and rain spreading onto the Brecon Beacons NP from the SE by late morning. Negotiations then ensued which established there were some conditions i.e No long walks in head torch light, the location should also minimise walking, the location should minimise travel and maximise sleep …   I explained that with sunrise at 08.20'sh, somewhere on the moorland on Mynydd Llangynidr would minimise walk time from the car to a decent viewpoint and Mynydd Llangynidr was the one of the closer options for the Brecon Beacons NP, so a plan was hatched, we will call this Plan A. 

Setting out later than expected, she wasn't going to be hurried and there was no little indecision about what to wear, which meant repacking and changing for conditions that wouldn't be of arctic severity. The car journey suggested that low cloud was already well on its way and there were fog/mist patches, which slowed travel down. I muted an option of Plan B a quick drive up to the Blorenge, mostly to see if the Black Mountain were clear and assess how thick the cloud layer was, oh and catch the sunrise colour. I was informed that we had visited this locale a few weeks before and told to stick to Plan A. Pity, as a break in the fog/mist revealed broken cloud with that tinge of magenta. As so often of late, Plan A utterly unravelled as the cloud/fog was extensive on the Heads of the Valleys Road and the mountain road barrier at Trefil was shut and locked. Plan B was needed - Table Mountain above Crickhowell was considered and rejected in view of the incoming cloud. Plan C - get somewhere high enough and as far away from the incoming low level cloud as possible. 

Dropping down into the Usk Valley from Cwm Onnau and the Black Mountains were clear of cloud, some patchy valley mist in the Rhiangol valley, a high layer of broken cloud was overhead and the sun was shining. So,  Mynydd Troed an outlier of the Black Mountains would be Plan C. 

Views from the North side of Mynydd Troed.

Castle Dinas

Western escarpment of the Black Mountains

Views from the South side of Mynydd Troed 

A wise decision to abandon Plan A 

Valley mist in Cwm Sorgwm

Views over to the Brecon Fans

Cloud streaming up the Usk Valley

My technique was less than satisfactory, as I'd somehow adjusted the Iso setting to a value beyond optimal, though not an unacceptable Iso speed, the error was spotted and readjusted. I'm not sure how this happened, as I thought the camera set up fool proof, hmmm gloves maybe? Worse, in a sequence of long tele photo images, some were 'soft'. The fact that some were sharp, pointed to the tripod technique and I'm opting for a combination of soft ground - 'springy' moss, peat and a stiff breeze as contributory factors, these aren't uncommon ground and wind conditions in uplands and I should have adapted my technique accordingly, mea culpa.

Brecon Fans disappearing

With the wind increasing and pushing the cloud onwards, Mynydd Troed was overwhelmed and with limited visibility a compass bearing taken and followed back to the car. Plan C delivered a great vantage point to witness a weather phenomena and an excursion, albeit cut short, that was thoroughly enjoyable.