Mapping Mountains – Trimble Surveys - Pumlumon

09.01.14  Bryn y Fedwen (SN 840 953) and Foel Fadian (SN 828 953)

Foel Fadian (SN 828 953)

After celebrating a 53^rd birthday with friends and live music in Llanidloes with a welcome sleep over.  The following morning we then watched the rain sweep in from the west as the hills around the town turned grey and uninviting.  Patience and numerous cups of tea paid dividends as by midday the rain had ceased and we ventured out to visit two Deweys close to the Glaslyn Nature Reserve on the northern side of the Pumlumon range.

Accompanying me on the walk was Eryl, a good friend that had dragged me out on numerous hill walks and exotic treks over a period of more than twenty years.

The walk wasn’t planned to be adventurous, just a wander on quiet hills with good conversation and hopefully a view or two thrown in for good measure.

As we set out the cloud base was below the summit of Foel Fadian and the winter mist quickly descended toward our first objective; Bryn y Fedwen.  By the time we arrived on the summit the hill was bathed in ethereal mist with breeze blowing the surrounding land. 

Looking toward Glaslyn from the upper slopes of Bryn y Fedwen.

The summit area has a relatively large ancient tumulus at its highest point measuring an approximate 20m by 18m and about 1.5m high.  Near the highest point is a boundary stone. 

The Trimble GeoXH 6000 on the high point of Bryn y Fedwen.

As the Trimble achieved its 0.1m accuracy before the time when the button is pressed to start gathering data, Eryl sauntered off down the eastern ridge to see if there was any bird life on the hill.  By the time five minutes of data had been gathered he was venturing back through the mist toward me.  Nothing exotic had been seen but we had disturbed a red grouse earlier, somewhat of a rarity around Glaslyn as supposedly there are only a dozen or so nesting pairs in this area of the Pumlumon range.

As I headed off to the bwlch between Bryn y Fedwen and Foel Fadian, Eryl headed towards the car for a flask of coffee and mince pie and occasionally peered out at this lone figure standing in a wet bog who waited for this piece of equipment to say 0.1m accuracy achieved and then 300 points collected.  This process took an age, much longer than previously experienced during the surveys over the last few weeks.  At least I had time to admire the surrounding bog of heather, emerald moss and standing water.  Even the dry bits were wet and boots sank in to water wherever I stood.

The critical bwlch of  Bryn y Fedwen is a particularly boggy place.

Re-joining Eryl we picked up a path through the heather toward the summit of Foel Fadian.  The highest point of this hill is beside the trig pillar on close cropped grass.  We took shelter on the leeward side away from the cold wind as the Trimble gathered ten minutes of data.  From this vantage point the northern escarpments are on fine display.  These and the wildness of the surroundings are the ranges real highlights.

Eryl beside the trig pillar on the summit of Foel Fadian.

The wild surroundings of Glaslyn with part of the northern escarpment of the Pumlumon range plunging downward.

After closing off the Trimble we headed down the hill toward the comfort of car, dry clothes and more conversation and tea.  It proved an excellent night and enjoyable walk.



Survey Result:

Bryn y Fedwen

Summit Height:  543.8m (converted to OSGM15)

Summit Grid Reference:  SN 84066 95338

Bwlch Height:  509.0m (converted to OSGM15)

Bwlch Grid Reference:  SN 83631 95310

Drop:  34.8m

Dominance:  6.40%

Foel Fadian

Summit Height:  563.9m (converted to OSGM15)

Summit Grid Reference:  SN 82831 95364

Bwlch Height:  475.0m (converted to OSGM15, from subsequent Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SN 82848 92131 (from subsequent Trimble GeoXH 6000 survey)

Drop:  88.9m (converted to OSGM15)

Dominance:  15.76%




For details on the bwlch survey of Foel Fadian 

For further details please consult the Trimble survey spreadsheet click {here}