The Greatest Cwm - Idwal

now in the ownership of the National Trust - this is a must do walk for anyone who visits Snowdonia

The rocks of Cwm Idwal were formed over 400 million years ago, when North Wales was a land still underwater and being formed by volcanic explosions.

Charles Darwin visited Cwm Idwal in 1831, and observed that the large, scattered boulders at Llyn Idwal contained marine seashells. He realised that the rocks must have formed within an ancient ocean, and therefore had been later uplifted to the surface by forces within the Earth’s crust.

Darwin later returned to the area, and made a further observation- that the beautiful landscape of Cwm Idwal was shaped by glaciers, at a time when Wales was far colder than it is today.
Glaciers move incredibly slowly, and carve steep-sided valleys as they erode the rock beneath them. The larger the glacier, the deeper the valley it can erode; where small glaciers feed into a larger glacier system, small ‘hanging valleys’ are created high above the floor of the main valley. The word “Cwm” is Welsh for valley, and Cwm Idwal is a striking example of a glacial hanging valley.

Cam Idwal is surrounded by the high peaks of Y Garn and Glider Fawr, and lies in the Glyderau mountain range.

Llyn Idwal, measuring 800 metres long by 300 metres wide, is surrounded by towering high crags, screes, glacial moraines and wind shattered rocks.

Named after Idwal, the son of one of the ancient Princes of Wales, Owain, Prince of Gwyneddd, legend relates Idwal was murdered by being drowned in the lake. Tradition further states that no bird flies over the lake, as a result of Idwal's terrible fate.

The dark and brooding cliffs of Cloqwen y Geifr ( the Cliff of the Goat) form a dramatic backdrop to the lake. The plume of steam that rises from a crack in the towering rocks above, bestows another name on the area- Devil's Kitchen.
The steam, however is the result of moist air coming into contact with the rock face, forcing it upwards, causing it to cool and condense to form swirling clouds.

Devil's Kitchen is known in Welsh as Y Twll Du, meaning black hole. You can see why it was once thought to have sinister origins - today though you're more likely to see the bright coloured jackets of hikers scrambling up the gorge

It's the most dramatic low level walk in Snowdonia - and the commissioned gate at the entrance to the Cwm makes it even more magical

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