I psyched myself up for the very steep climb of 600' that begins at the road footpath sign and zigzags up through the trees of the Coed Dolgarrog nature reserve near the large twin water pipes. At a stile the pipes continue their ascent at an easier angle to a good contouring track that makes an attractive and refreshing open walk around towards Coedty reservoir, following the course of a leat. The snow covered top of Carnedd Llewelyn peeped out beyond Craig Eigiau across the valley of the Afon Porth-llwyd.

The track provides an easy and attractive walk into the valley beneath the flanks of Moel Eilio and curves around to the breached dam wall by Llyn Eigiau, a surprisingly shy lake for its size that stays hidden until the last minute. Opposite are the cliffs of Craig Eigiau while Pen yr Helgi Du dominates the view in the upper Cwm.

I took the surfaced track down the NW side of the valley to the little car park and the side track that ascends gently to the foot of the NE ridge of Craig Eigiau. The track climbs around the northern flank and turns into the next valley, home to Melynllyn and Dulyn reservoirs, where I left it to follow Craig Eigiau's NE ridge. The summit is a fine elongated spiky rib of rock with a good view of the hills, and is easily attained.

Foel-fras and Foel Grach appeared to have just a light dusting of snow left on their tops but Carnedd Llewelyn retained a significant cap: I was wearing my summer Mids but I had packed the Microspikes and reckoned I should be fine. I saw one walker in the distance ascending towards Llewelyn, the only other walker I would see in the whole trip.

The map shows no path on the ground ascending to the main ridge from this side, my first approach on this line, but there is a clear path from the 730m contour across the broad expanse and up the obvious nose above Melynllyn reservoir. Nearing the ridge, the path disappeared as I met the snowline - it emerges a little south of the bwlch between Llewelyn and Foel Grach - and the mist was gathering, intermittently engulfing the stony landscape and blown in on a biting wind.

I managed to capture an atmospheric shot of Yr Elen against a turbulent sky before Llewelyn clagged out during my final climb to its windswept plateau. It's hard to think of a bleaker place in poor conditions, but a magnificent one nevertheless.

I was soon off down the SE ridge where the snow was thinner and more patchy than expected: I didn't need the Microspikes after all. Just beyond the initial descent is a cairned hillock and I headed towards the edge overlooking Cwm Eigiau to find a pitch on the snow-dusted grass near its foot. Llewelyn cleared shortly afterwards but not for long: by dusk the thick mist had shrouded the whole area but the temperature dropped rapidly. At around 3000' I hoped for an inversion the next morning.

As if to order, at dawn the sun peeped over the ocean of cloud that had settled into the valleys and cwms far below, stretching as far as the eye could see to the east. The tent had furled into ripples under the thick frost and I made a hot drink: time to get moving early before the sun gained strength and evaporated the spectacle.

The SE ridge traverse over Craig yr Ysfa, Pen yr Helgi Du and Pen Llithrig y Wrach is always a superb walk but simply magnificent today. The clarity above the cloud was excellent and the ridges and summits of Moel Siabod and the Glyderau were bold and sharp above the white mantle. I was grateful that the slightly awkward manoeuvre on the descent of Craig yr Ysfa was dry and free of ice or frost.

Descending Pen yr Helgi Du, the mist had risen somewhat and spilled over Bwlch y Tri Marchog, but I soon emerged again into blue sky and clarity for a longer than usual break on the summit of Pen Llithrig y Wrach for a bite to eat in the now quite warm sunshine.

While sitting on the summit I heard the unmistakable sound of a helicopter - I had heard it twice the evening before in the tent - this time it rose out of the mist somewhere above Llyn Cowlyd and flew up towards Llewelyn.

I descended the south ridge to the shoreline track along Llyn Cowlyd and stopped to take off my base layer Powerstretch, such was the warmth of the sun. The lake was covered in mist and invisible from the summit but it was practically all gone now, leaving a hazy view, while the pools in the rocky parts of the track had extensive frogspawn.

On our last visit to Cwm Eigiau, we tried to follow the byway from the dam on the NW side of the pipeline and it was a tortuous failure. This time I took the dam access track to the T-junction at SH744642 and turned L uphill to follow this good track NE all the way along the valley, and as I had seen from Google Maps, this led me directly to the top of the water pipes descending the outward route back to Dolgarrog. The only choice comes at a bifurcation just after crossing a track bridge over a small ravine around SH762660: here take the R lower fork.