Strange as it might seem, the biggest ice feature in Wales is not to be found up in the mountains, rather it is hidden away at the back of a surprisingly benign looking valley which branches off from the A470 road near Dinas Mawddwy. The classic route here is a grade IV which winds its way up the huge icefall in six wonderful pitches. When it comes into condition word soon spreads; consequently getting the icefall all to yourself is unlikely. This does make for a sociable ascent but the down side is that bombardment from falling ice is probable, especially if there are any inexperienced members in the team above you. So, position your belays carefully (out of the firing line if possible) and keep your eyes peeled for any tumbling chunks. And if you get there first, be careful what you knock down on those below.
Several variations on the guidebook line are possible, all at a similar grade to the original. That being said, sketchy ice may be encountered if you stray to far off to the side from the main icefall.
The base of the fall is relatively low so a proper sustained freeze is required before the route comes fully into condition. As with any icefall, an ascent in thin conditions is not recommended.
The walk into the crag from the lay by on the A470 is not too arduous. There is a designated route though – please check the BMC Regional Access Database for full details prior to your visit.