All walks › Eryri: Yr Wyddfa and Llanberis
Eryri: Yr Wyddfa and LlanberisElidir Fawr
A long steep climb to the summit above the Dinorwig pumped storage scheme, with a reservoir hidden in the cwm and the whole of the Glyderau to the south.
- Distance
- 6.2 mi / 10 km
- Time
- 5 hr
- Ascent
- 850 m
- Difficulty
- Strenuous
- Shape
- There and back
Where it is
The circle shows the general area, not the exact start. Use the directions link below to get to the car park itself. Contours and paths shown are OpenTopoMap, drawn from OpenStreetMap data.
The route
Climb from Nant Peris up the western flank on a steep and often pathless line to the summit ridge. back down the outward line; the alternatives involve crossing quarry land.
Worth knowing
- The mountain is hollow: the Dinorwig power station is built inside it, in the largest man-made cavern in Europe.
- Marchlyn Mawr in the northern cwm is the upper reservoir and its level rises and falls daily.
- Steep and loose in places. One of the tougher ascents in Eryri for its height.
What you’ll see
Marchlyn Mawr in its cwm, the Llanberis Pass below, and the Glyderau ridge opposite.
Background
Dinorwig power station opened in 1984 and can go from standby to full output in sixteen seconds, the fastest response of any station in the world at the time.