Tucked in on the northwest side of the Nantlle Ridge there is a beautiful cwm ribboned with a run of excellent ice climbs. The number of quality routes here rivals those found in Cwm Idwal and if there were a few more in the lower grades Cwm Silyn would surely be just as popular. As it is the better routes here are in the grade IV to VII range. If you’re comfortable at that level then you are in for a treat as some of the best ice routes in Wales can be found here.
A good sustained freeze is needed to bring the routes into condition. The Craig yr Ogof side of the cwm does receive some sunshine so ice formation and retention can be quite fickle here. The central and right side of the cwm is much shadier and consequently the ice is less likely to melt out. Colin’s Gully IV/V 5, Bedrock Gully IV/V 5 and The Mask of Death V/VI 6 are the first major lines to come into condition – luckily they are also some of the finest routes in the cwm.
The crag is best reached from Llanllyfni, which is just south of Pen y Groes. A series of minor roads lead to a parking spot just beyond Bryn Gwyn Farm. From here it is possible to walk into the crag along the obvious grassy track.