Map showing the location of the great slab on Cloggy

Clogwyn Dur Arddu - Great Slab

A great crag and a great route, aptly named the great slab. There is only one technically demanding section up an often-damp corner. The route is long with a lot of variation possible.

Grade VS 4c
Length 162m
Pitches 5
Approach 120min

The Route Topography

This is the route Great Slab on Clogwyn Dur Arddu in Gwynedd, Wales. It represents 162m of Rhyolite rock climbing, usually over 5 pitches, of a max grade of VS 4c. Clicking the image will load the full screen high resolution Great Slab climb topo.

Original Image: BMC super zoom

Approach & Descent Information

From Llanberis either take Britain's only Rack and Pinion Railway to the Halfway House, or make the walk from Llanberis. Walk up the road opposite the Royal Victoria Hotel, then take the path left which runs parallel with the Snowdon Mountain Railway. After the Halfway House a miner's path breaks off right to coast beneath the crag and above picturesque Llyn Du'r Arddu. Beware of rock fall. Calculate 2 hours for the walk-in.

See Clogwyn Dur Arddu on the climb map Open climb location in Google Maps


North Wales Climbs

North Wales Climbs - pg. 149

If you could only own one book on multi-pitch climbing in the UK this book would be a great choice. North wales has pleanty of Trad climbs above 50m. The book covers a good selection of climbs on each crag including Cloggy.

Availible Here R.R.P. £ 24.99
ISBN: 9781873341827

Weather & Local Conditions

The climb Great Slab on Clogwyn Dur Arddu suffers from seepage and will need time to dry out after rain. Rock climbing after heavy rainfall could be a slimy unpleasnt experiance.

Seasonal Weather Information

Note that some weather stations are close or even on the mountain, others are in nearby towns. Plan accordingly!

Estimated Rainy Days Per Month

  • 13
  • 10
  • 11
  • 9
  • 8
  • 8
  • 8
  • 9
  • 10
  • 14
  • 14
  • 14

The graph shows the estimated average number of rainy days in the month that had more than 1mm rainfall or snow:

Estimated Temperature Per Month

  • 83
  • 82
  • 93
  • 124
  • 157
  • 1710
  • 1912
  • 1812
  • 1710
  • 138
  • 105
  • 83

Estimated average high and low temperature in degrees Celsius for the given month.

References & additional links

The following links will take you to external websites specifically related to this climb: Great Slab on Clogwyn Dur Arddu.
Note: They contained relevant information at the time of publishing.

Clogwyn Du'r Arddu on UKC

BMC Supper Zoom topo of Clogwyn Du'r Arddu

Rockfax preview covering the Great Slab climb on Cloggy

Listed Nearby Climbs

The are some top quality multi-pitch rock climbs nearby. Guidebooks (see above) will have a more comprehensive list of other local climbing venues.

Ordinary Route on Cwm Idwal
140m climb graded D 3a.
6km away

Longlands Continuation on Lliwedd
280m climb graded S 4b.
3km away

Australia West Face on Dinorwic Quarry
113m climb graded E1 5b.
5km away

There are currently over 40 published multi-pitch climbs on the site.

View All Listed Rock Climbs