Glaslyn — the green-blue lake beneath Yr Wyddfa's summit, at 600 metres in the eastern cwm — is extraordinary in any light, but in early morning, before the first walkers arrive, its copper-green colour is most vivid and the surrounding ridges most perfectly reflected. This is one of the genuinely transportive experiences available in Eryri. This is Experience #21 of the Snowdonia 100.
Getting There Early
To reach Glaslyn by dawn from Pen-y-Pass requires a pre-dawn start of around 90 minutes. The Miners' Track is the most direct approach, following the old mining road past Llyn Teyrn and Llyn Llydaw before climbing to Glaslyn's outflow. The lake is at 600 metres, well above the cloud inversion that sometimes fills the valleys in still autumn weather — arriving above it as the sun rises over the Llydaw ridge is one of the finest visual experiences available in the mountains.
The Colour
Glaslyn's copper-green colour comes from copper minerals dissolved from the ancient volcanic rocks of the cwm — the same minerals that were extracted at the Glaslyn copper mines that operated from the 1760s to 1916. The concentration varies seasonally, the colour most intense in dry summer conditions when the water is clearest. At dawn, when the lake surface is still and the low light catches the green-blue tones, it looks otherworldly — something from an illuminated manuscript rather than a real landscape.
Practical Notes
The Miners' Track to Glaslyn is well-surfaced and straightforward with a headtorch. A high-pressure weather window with clear skies and no wind is essential for the best reflection. Check the Mountain Weather Information Service the evening before. Bring a flask. Return via the same route or ascend to the summit for the full sunrise experience.
Experience #21 of 100 — Water and Light category.
Independently written — Snowdon.com