Llyn Idwal is a small glacial lake in Snowdonia, easily accessible from the A5. The path begins at Ogwen Cottage at the foot of Llyn Ogwen, crosses a stream and then turns right after a quarter of a mile in to Cwm Idwal, a dramatic valley surrounded by the crags of Glyder fawr, Twll Du (‘The Black Hole’ or more popularly known as ‘the Devils Kitchen’) and Y Garn.
Although Llyn Idwal is half a mile long it is only 36 feet deep at its lowest point, and over 60 percent of the lake is less than 10 feet deep. It is held back by a large terminal moraine, and the western shore has the remains of lateral moraines (glacial debris). One of these lateral moraines is said to be the grave of the giant Idwal.
There is a legend that the lake is connected to Cadwaladar ap Cadwallon’s son Idwal Iwrch (Roebuck) who was the father of King Rhodri Molwynog (died AD754). The records of this period are scant unfortunately, and Idwals name appears only in the pedigrees of later kings, and in a prophecy discovered in two 14th Century Welsh manuscripts which say that he will succeed his father Cadwaladar as King.
The oldest learned account of how the lake was named tells of Prince Owain Gwynedd, who had is son Idwal, fostered by Nefydd Hardd (Nefydd the Handsome) of Nant Conwy. Unfortunately, Nefydd failed to look after the boy and he drowned in the lake. As a consequence Nefydd was degraded to the rank of bondsman and had to give up all of his land and posterity.
The Devils Kitchen gets its name from a sinister plume of steam that can be seen rising from a crack in the crags. This is actually due to moist air coming in to contact with the rock face, which forces it upwards where it condenses to form swirling clouds. It is said that the Devil beckons weary travellers into his kitchen, and they are never seen again, and that birds do not fly above Llyn Idwal because of the death of the Welsh Prince Idwal.