Mapping Mountains – Trimble Surveys – Banc Llechwedd Mawr

 

03.09.25  Twyni Mawr (SN 606 938) 

Twyni Mawr (SN 606 938)

Blanks on the map can be interesting to investigate.  These are the places that Ordnance Survey designate in flux, as in the ground they inhabit is unstable.  These include quarries, landfills and other places terra-formed by human interference.  However, they also include places that have not been altered by man’s need to make big holes or bury a lot of stuff in the ground. 

The blank on the map

Nowadays other online mapping show contours for such places, this gives perspective to the lay of land.  Today I was visiting friends and if the weather acted kindly we planned on visiting one of these blanks on the map.  I mention the weather as leaving Welshpool and driving west the cloud base soon closed in with drizzle becoming ever more present.  Approaching the coast this turned into heavy showers with the narrow roads leading to Ynys-las becoming water-logged.  I suppose after an unseasonably warm summer, a bit of rain was a change! 

Extract from the interactive mapping hosted on the WalkLakes website

I was heading to the Searivers Caravan Park, where Eryl and Rita were enjoying a few days relaxation, including coastal walks between what was proving to be a particularly wet spell of weather. 

The Searivers caravan site at Ynys-las

By the time I pulled up outside their home from home the rain was bucketing down, so much so that I ran from the car to the front door and hoped it was opened without delay.  The next hour or so I was very happily settled on a chair, with a mug of tea and assorted biscuits at hand as we caught up with all manner of things, whilst the rain continued to fall.  As time progressed a glimmer of semi-brightness appeared out to sea, this quickly pushed inland and heralded a tempting flash of sunlight as the rain calmed its deluge.  Rita said; ‘right if we’re going to go we need to get ready and make the most of whatever dry spell we have’.  This we did, and soon were walking through the site toward the narrow dead end road and the gate on its opposite side which gives access to the complex of dunes.

Prior to my visit I’d examined this blank on the map via LIDAR, building up the coloured contours until the high point and the connecting bwlch of these dunes was found.  LIDAR gives this point as having 18.4m of drop, so it easily qualifies as a Welsh P15, whilst maps record the name of Twyni Mawr for this area, which is apt as a translation of this can be big dunes. 

LIDAR summit image of Twyni Mawr

Whatever the occasion it’s always good to see Eryl and Rita, whom I’ve shared so much with over the years, especially so with Eryl; including travelling and treks around the Alps, Nepal, Tibet, Vietnam and Cuba, nowadays our ambitions are reduced, but the friendship is still strong. 

Information board at the access to the dunes

Our access to the high point of Twyni Mawr was via a wooden walk way which continues to the coastal sands and the sea beyond; where the walk way crests the dunes a convenient bench had been installed.  Not surprisingly this point gives extensive views out to sea and also inland to what today were cloud enshrouded hills.  Although the view was to be admired the cloud out to sea looked like more showers were on their way, so not lingering I followed Eryl as he started down the walk way whilst suggesting the best way to the high point of the dunes was to cut back using one of many valleys that interweave amongst the dunes.  Eryl had investigated some of these and cautioned that when in them it’s hard to know where exactly you are. 

The wooden walk way heading into the dunes

The path beyond the high point of the wooden walk way

Leaving the walk way we headed into the dunes and accessed the valley directly below the western flank of the high point.  It was here that Eryl stayed, watching me and Rita as we headed the short distance across the valley to the base of the steepening dune.  

The valley leading to the high point of Twyni Mawr.  Photo: Eryl Selly

Heading toward the summit of Twyni Mawr.  Photo: Eryl Selly

I’d brought an umbrella, which is a norm for me even on some higher hills, as if confronted by rain it can shield my camera equipment much better that a Goretex coat, and although it was never used today as whatever rain did come across was never heavy enough to seek protection, it proved an ideal replacement for a walking pole for Rita, who used it to steady herself as we slid ourselves uphill on the steepening sand dune.

Once at the top of the steep bit it was only a short walk on a narrow path across the ridge of the highest dune to its summit.  Here we posed for the customary photographs before continuing on the narrow ridge path back toward where Eryl was patiently waiting for us on the wooden walk way. 

At the summit of Twyni Mawr.  Photo: Rita Selly

Heading back to the caravan the whole adventure had only taken 55 minutes, and we were ever so lucky with the weather as only a skidding light shower had blown across the land whilst on the dunes, which was fortunate considering how heavy the showers had been on my way toward Ynys-las and on my arrival.

We ended the day with a trip into Aberystwyth for a lunchtime meal at the University Art’s Centre before settling down to watch The Roses in the cinema.  It even brightened up for our drive back to Ynys-las and my continued journey to Welshpool.  It proved an excellent day out. 

 

Survey Result: 

 

Twyni Mawr 

Summit Height:  22.8m (LIDAR) (significant height revision)  

Summit Grid Reference:  SN 60614 93828 (LIDAR)

Bwlch Height:  4.4m (LIDAR)

Bwlch Grid Reference:  SN 60576 92484 (LIDAR) 

Drop:  18.4m (LIDAR) (Welsh P15 addition)

Dominance:  80.55% (LIDAR)

 

 

For further details please consult the Trimble Survey Spreadsheet