2013-14 part 3: January-February storms -
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|It's March 22nd
(Happy Equinox!) and here's the final round-up of the
incredibly stormy winter of 2013-14. I've not known one
like it in my fifty-plus years. Recently I wrote a
timeline on the winter for the climate science website
Skeptical Science and, having only included days when
wind-gusts reached 80mph or more, it was still one of
the longest posts I've had on there!
I covered most of the extreme wind damage swathes in the last post but more kept coming to light: one particularly impressive area of devastation is covered below. But the prime focus of this post is on the interesting discoveries I made along the coast at Tonfanau (165 million year old driftwood) and Borth (some superb new ancient footprints in the peat of the Submerged Forest) after the rough seas subsided. The beaches hereabouts (in fact pretty much everywhere around the UK) have been so comprehensively rearranged by the mountainous swells that they have become a fossicker's delight.
The process of putting one's life back together following a major bereavement is not an overnight thing, but there are certainly things that help and going to one's favourite/most interesting places is an important part of that. So late February 2014 saw me making a start by heading over to Tonfanau for a bracing walk along the beach: here's the view south over the estuary of Afon Dysinni towards Tywyn. The beach at Tonfanau is accessed by a footpath that crosses the railway by the station, then heads down towards the river mouth where you go through a gate in the fence and onto the shingle....
...or used to. A large part of the fence had been flattened by the overtopping waves, and the field was covered in shingle and small boulders....
Walking north along the top of the beach, the soft cliffs had been eroded greatly in places and - as a geologist - this made them well worth a look, with good clean, fresh sections to examine. Tonfanau is an important site in the realm of Quaternary geology - covering that period of geological time that began 2.55 million years ago and including the many glacial and interglacial cycles. What is special about the place is that during the last glaciation, the great ice-sheet that came down the Irish Sea hardly ever abutted onto the land, except, in northern Cardigan Bay, here. Thus the ancient glacial moraine deposits, that make up the darker basal part of the low cliff backdrop to the beach, contain all sorts of rocks derived from the floor of the Bay and further afield.
Furthermore, Cardigan Bay was a marine basin 165 million years ago in the Middle Jurassic period, and the moraine includes chunks of buff, Cotswold Stone-like limestone dating from that time (two prominent boulders of it are in the LHS of the photo below). Glacial ice is a very capable agent of erosion and as it ground its way across what is now Cardigan Bay, chunks of what is now the seabed (it was above sea level at the height of the ice age) - including the Jurassic limestone - were gouged out and dumped with all the other rocky debris here at Tonfanau.
What was it like here when that limestone was being deposited? Well, during the middle Jurassic, Wales lay at a latitude similar to that of North Africa at the present day. The climate was tropical and off its coastline there was a warm, shallow sea teeming with life, on whose bed sediments were being deposited which would eventually consolidate into the limestones.
The limestones contain local accumulations of fossil wood, the presence of which indicates that they were probably deposited quite close to an ancient Welsh coastline where the trees would have grown.The image below shows a newly-eroded out block containing, amongst abundant shelly debris, a rare length of a branch. This, then is quite literally a piece of driftwood that is about 165 million years old!
All sorts of other rock-types are to be found here: perhaps the most exotic are the rare boulders and pebbles of high-grade metamorphic rock, reminiscent of the ancient, 2-3 billion year old rocks of NW Scotland. They consist of quartz, pink and white feldspars, glittering spangles of white and black mica and, in some cases, garnets - small examples of which are visible (small, intense red areas) in the photo below.
There is one area on the beach, usually covered over by sand, where a number of large blocks of these metamorphic rocks lie embedded in the moraine, like the one in the image below (found in 1998), which is about half a metre long. Its more angular-looking underside is where it was embedded in the clay matrix of the moraine. The general scarcity of high-grade metamorphic rocks, and the occurrence of so many of them in the one spot, has led me to suspect that it all arrived together in one mass of ice - perhaps an iceberg, calved off some far-distant glacier and incorporated into the ice-sheet - that subsequently grounded here and, melting away, released its payload of rocks that it had brought from far away.
So that was Tonfanau. Elsewhere there has been plenty to investigate and photograph. One of the most impressive damage-swathes from the great gale of February 12th was at the chalet-park at Talgarth, near Pennal, in the Dyfi Valley. The damage track began near the farm of Glan-y-morfa, where these hardwood trees were snapped or uprooted....
Along the field edge leading into the Plas Talgarth grounds more trees were snapped or blown over...
In the grounds themselves though, there was an almighty swathe of near-total destruction, involving hundreds of trees:
The total damage-track from start to end, no more than 40-50 metres above sea-level, was some 500m in length. The damage would - had this been a TORRO tornado site-investigation - have been classified as a T4/F2 tornado with winds of at least 115mph - but, and this is where it gets complicated, the conditions on the afternoon of the 12th were non-conducive to tornado formation. The most intense ten-minute average wind recorded on the 12th was 82mph, gusting to 106mph, at the exposed Aberdaron weather-station in NW Wales. Yet here is some exceptional damage. Eyewitnesses told me it all came down in a period of an hour or two. Again - a point I made in my last post on these storms - once such winds get into a softwood plantation, the weaker, inner trees fall easy prey to the gusts compared to the more resilient outer ones, but damage to the hardwoods showed that some particularly violent gusts did occur here. Perhaps the topography had a role to play. Research is continuing into this storm and how it evolved, and there may well be answers to these questions in due course.
On the 26th, a few of us walked along the Wales Coastal Footpath from Glandyfi and on via back-lanes to Talybont. Above Caerhedyn, in the Llyfnant Valley, the path was a bit of an obstacle-course:
Luckily, a lot of these beautiful old sessile oaks had survived the storms:
Late winter sunshine on the path as it drops from Foel Fawr down into Cwm Einion:
On the 28th - the last day of the "100 Days of Heavy Snow" winter, so confidently predicted by the Daily Express back in November, the weather-gods obliged a teensy-weensy bit! The Tarrenau from above Derwenlas:
Onto Borth. Locals and visitors alike know the Submerged Forest well: some of it is on view almost all of the time somewhere along the beach and every winter more is visible following gales. In January 2007 a very large area of it was well-exposed off the village, and this year a major section has been unveiled off the northern part of Borth and up towards Ynyslas. Portrayed by some sections of the media as a "new discovery", much to the amusement of many locals, it is nevertheless something that only happens periodically, and it drew many visitors to come and have a look. The stumps, peat and pools make great subjects for the camera and it was impossible to resist a few visits!
At the seaward end of the forest, wave erosion shows the sequence with peat, between 6000 and 3500 years old, sat atop clay of brackish water origin:
These features thus record the transition from salt-marsh/estuarine conditions to wooded fen to blanket peat-bog and finally beach: silting of the marsh is an explanation for the initial stage, followed by, sometime later, water-logging of the woody fen and finally the advance of the coastline landward over the whole lot.
Exposed surfaces of the clay are heavily bored by piddock-shells:
In early 2012, at the far
southern end of the beach, father and
son, geologist and archaeologist Drs.
Dennis and Martin Bates discovered a
localised area of burnt stone scatters
and footprints, including those of
humans, in the upper part of the
peat-bed in which the tree-stumps are
embedded. Other prints included those
of sheep, cattle and goats. With
fellow archaeologists from the
University of Wales, Lampeter, where he
lectures, Martin Bates
surveyed and excavated the site, now
believed to date back from the Bronze
Age. I covered that find in a
On 28th February this year, in the area north of the village, I made a new find:
It included some superb imprints of cloven hooves:
This is a possible human footprint:
At some previous point when the peat-beds were uncovered, a large tracklaying machine had driven over them. Contrast the depth of the footprints above with the impression made by this multi-tonne machine - that peat is extremely compact today. Jumping up and down on it in heavy rigger-boots makes no impression at all.
The huge storm-swells and their undertow literally dragged most of the sand of Borth Beach offshore as this image shows. Taken at the water's edge, a large lagoon sits below the low water mark, with the sand forming a large bar some 200-300 metres offshore, over which a heavy surf is still breaking:
It'll be interesting to see how the beach reassembles itself in the coming months. Already, the sands are slowly coming back onshore, covering parts of the forest again. Hopefully this will continue as right now the beach is extremely difficult to fish, given that it is necessary to have bait in the surf or even beyond it!
Over at the garden, there was the matter of the poor old shed, victim of the 12th February windstorm. Taking a chainsaw to the tatty remnants seemed the most effective way to deal with it!
And done! Amazingly, the greenhouse is salvageable - I was quite surprised given that it resembled an airship disaster. With a hacksaw, a roll of gaffer-tape, some rigid steel bar as splints and a bag of cable-ties, the frame was reassembled elsewhere in the garden.
The place has been busy with bird-life, attracted by the food-supply. I'm sure all sorts visit the place, so first sightings for me have likely been feeding there for weeks quite happily, like this coal-tit!
One morning I took a long lens with me, intending to get a better shot, and was rewarded when this pair of long-tailed tits turned up. I'll be back there next sunny day - it is cold, overcast and windy with frequent hail-showers today.
So that was winter 2013-14. One of the mildest on record, quite possibly the stormiest, certainly the wettest (in fact it was the third wettest season in the England and Wales Precipitation record going back to the late 1700s). What will spring 2014 bring? Hopefully some warm sunshine, because I have a garden to plant, but unlike Daily Express writers, I'm not making any long-term predictions! More soon....
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