Myrddyn Phillips - Mapping Mountains: Mapping Mountains – Trimble Surveys

Saturday 9 September 2023

Mapping Mountains – Trimble Surveys – Carnedd Wen

13.07.23 Yr Allt (SJ 242 100, previously Trimbled)

Yr Allt (SJ 242 100)

It was my pleasure today to join Sarah Kerr on part of her Offa’s Dyke walk. Sarah had contacted me a few weeks ago and asked if I would like to join her for a few hours as she was walking part of the long distance footpath north of Welshpool.

Considering how wet recent days have been we were ever so fortunate with the weather as although an occasional slow moving shower was forecast for parts of Wales, any grey cloud that materialised did not develop in to rain and our walk remained dry.

Sarah Kerr

I met Sarah at 8.30am on the Rhallt Lane outside the recently built and large property where she overnighted. The morning was beautiful with blue sky and the hint of warmth in the air. It was good to see her as the last time our paths crossed were a number of years ago when trips to Welsh islands and lighthouses were organised.

Prior to meeting I suggested the possibility of including an ascent of Yr Allt from the Rhallt Lane and dropping off the hill back on to the canal towpath which hereabouts also forms a part of Offa’s Dyke footpath. Sarah was on for this, therefore after pleasantries we walked up the steep lane chatting about all manner of things. The conversation must have been good as even though I’d been this way a number of times over recent years we overshot the footpath I planned for us to follow. This meant we remained on the lane as it turned in to a track and we followed it to its high point.

In the field leading toward the trig pillar

At the end of the track a footpath continues through undergrowth to connect with a forest track, however we now headed to our right on to a steepening field where wild flowers predominated, with a plethora of butterflies flitting this way and that in the warmth of the strengthening sun.

Approaching the trig pillar

This part of the field forms a ridge that leads ever upward to where the triangulation pillar sits confidently looking north-eastward out toward the Breiddin and the higher hills to the west. The western horizon was dominated by the Y Berwyn ridge with the higher Aran also on show, with their elongated ridge still battling with wisps of cloud which no doubt would soon be burnt off.

The distant Y Berwyn

Leaving the trig pillar we lost height heading toward the corner of the lower field, where a stile gives access to another field leading past the large mast that can be seen from many miles away signifying the summit area of this hill. Shortly beyond is the high point, it doesn’t afford the view that the ground beside the trig pillar does, but it is the summit and therefore with my bagging hat on it had to be visited.

Sarah at the summit of Yr Allt

To get on to our descent route we now doubled back to the trig pillar and followed the ridge downward past pheasant pens and the Gamekeepers Cottage at the end of the forest track. Down we went heading toward the Coppice Cottage where many a year ago I used to live. However, before the cottage is a forest track on the right that heads down through the wood. I had always wanted to investigate this track and see where it leads. Having already mentioned this to Sarah she had no objection to us investigating this route.

The track led us down through the wood and seemed to grind to a halt where summer undergrowth of nettles and brambles then took over. Just below us was a high pheasant fence which conveniently for us had been flattened due to a tree bow falling on it. However, between us and it was all manner of debris which entailed an assault course to get through, which we eventually did, emerging on to an open field and with the aid of mapping on Sarah’s mobile phone we were soon directed down the field to a footbridge crossing the canal.

After crossing the footbridge we had one barb wired fence to negotiate before reclaiming the canal towpath. Our onward routes now headed in opposite directions, Sarah farther northward following the footpath of Offa’s Dyke and southward for me back toward Welshpool.

Sarah heading off on the canal towpath to continue her Offa's Dyke journey

Before heading our separate ways we had a hug and I thanked Sarah for the invite to join her. It had been an immensely enjoyable few hours with good company, good conversation and a hill thrown in for good measure!

Survey Result:

Yr Allt

Summit Height: 231.3m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference: SJ 24240 10005 (from previous Trimble GeoXH 6000 survey)

Bwlch Height: 125.9m (LIDAR)

Bwlch Grid Reference: SJ 21855 08773 (LIDAR)

Drop: 105.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance: 45.57% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For details on the first Trimble GeoXH 6000 summit survey of Yr Allt

For details on the second Trimble GeoXH 6000 summit survey of Yr Allt

For details on the Trimble GeoXH 6000 bwlch survey of Yr Allt

For details on a third visit to the summit of Yr Allt