The steep zigzag climb directly from the car through the wooded nature reserve of Coed Dolgarrog doesn't get any easier, but the attractive woodland of native beech and birch was aglow with autumnal colour in the shafts of sunlight. The angle eases at the timber hut mounted atop a plinth above the twin water pipes where the Conwy valley comes into view below, finally reaching our contouring track that would take us around to Coedty Reservoir.

The track provides an easy and attractive walk into the Afon Porth-llwyd valley beneath the flanks of Moel Eilio and curves around to the breached dam wall by Llyn Eigiau. Alas this cwm definitely seems to be gaining popularity even in November: true, today was a sunny Sunday, but the car park on the far side was full and more cars were parked further down the road, disgorging whole groups of walkers and the odd day tripping family. From the dam area the broad valley displayed a rich variety of sunlit autumnal reds, browns and yellows.

A casual newcomer on the tracks hereabouts might remain unaware of Llyn Eigiau, a shy lake that requires a short diversion beyond the dam to gain a good view of its waters below the cliffs of Craig Eigiau. Very few bother to make the effort and we have always been alone on its shoreline, a lovely spot once past the trappings of the water management structures.

We put on our windshells for the north-easterly trek into the breeze along the valley to the car park, passing some groups of walkers including a few overladen backpackers. Come to think of it, on all our visits there has always been a minibus/van parked here, the area must be a favourite destination for outdoor activity centres.

On the track north-westwards from the car park, several lone walkers and another group were returning as we began the gentle climb around the shoulder of Craig Eigiau to the western side of the ridge. Here we left the main Llewelyn-bound path to ascend the Eigiau ridge directly and we were really surprised by several encounters with descending walkers: we have never seen anyone else on this line. The views to the higher Carneddau remained beautifully clear but the first small clouds were gathering.

Reaching the excellent rocky spine, we pitched the tent at the base and ascended to the uncairned summit for the grand views. A vocal raven repeatedly cruised us and later perched at the summit, staring down intently at our tent and cronking insistently, while a small group of wild horses grazed near a pool below to the north. Later the mist descended onto Carnedd Llewelyn as the sun sank behind the silhouetted skyline and the temperature quickly dropped.

In the night the mist had settled out below in the valleys and one thick patch could be seen in the moonlight bathing the scene from a starry sky, giving hopes of a reasonable inversion at dawn. As the sun rose most of it had dissipated locally leaving some wisps below and distant hints of a better view, but the air was crystal clear and the tent was thick with frost.

Despite the cold night the sun quickly became very warm as we walked over the expanse of Gledrffordd with its frozen pools, a superb morning walk with dead calm, total silence and a cloudless crystal clear mountain skyline. We briefly began to regret planning the route to descend from the high ground so early but the original decision would soon prove to be right.

We descended alongside a mountain stream towards the old quarry ruins in Cwm Eigiau amid casual glances from a herd of wild horses who showed little interest in our intrusion. The crags of Craig yr Ysfa were well seen from below as we approached the ruins where a couple of campers had pitched. Then we saw the first ribbons of mist appear from nowhere around Carnedd Llewelyn.

The track along the cwm is a fine easy walk with good views of the northern face of Pen yr Helgi Du and southern end of Craig Eigiau, our first time along this route, and a helicopter appeared at low level in the first of several passes up and down the cwm. The track crosses the Afon Eigiau at a bridge and approaches the dam, and looking back the cloud had filled in very quickly and completely.

The route now follows the mapped path behind the buildings of Hafod-y-rhiw and over the north-eastern shoulder of Pen Llithrig y Wrach towards Llyn Cowlyd, another new section for us. This path is clear initially as it winds its way cleverly aloft through the heathery landscape, but as the terrain becomes rougher and wetter in the contorted central part, it becomes vague and all but disappears in the matted heather and bog. After crossing a small stream head, the mapped line contours across to a metal gate in a stout wall, but we found the easiest line was a bit of a path ascending the small knolls on the northern fringe of Cribau and descending easily on grass to the gate. At some points on the traverse - by any line - there will be some brief squelchfests.

Through the gate, a path descends easily on the eastern side of the wall to the track at Garreg-wen. This track gives an easy walk out along the valley directly to the top of the water pipes descending the outward route back to Dolgarrog. No photos after Llyn Eigiau: the damp mist had enveloped everything.