Mysterious dark line spotted off coast like a'waterfall' in the sea

A WALKER admiring the views from Cader Idris, one of the most popular peaks in Wales, was left baffled by a dark line stretching out across Cardigan Bay last weekend.

- By ANDREW FORGRAVE Countryside and Tourism Editor

Continuing for miles, it appeared more enduring than a simple confluence of currents.

When he shared an image on social media, it sparked more intrigue. A Birmingham visitor had spotted it previously as he drove towards Barmouth following a trip to Shell Island, Europe's largest campsite.

"I looked out across the bay and couldn't believe my eyes," he said. "I had to pull off the road to look. I can only describe it as a waterfall that stretched clear across the bay to Abersoch."

Explanations online ranged from seaweed arrays to sewages discharges.

Some recognised it for what it was: a remarkable natural feature that, like a giant serpent, surfaces only occasionally - one said to have wrecked 500 ships and the boundary of an ancient lost kingdom.

Sarn Badrig (St Patrick’s Causeway), is the longest and most northerly of three reefs extending out from the west coast of Wales. From Mochras Point at Shell Island, near Harlech, Gwynedd, it runs out into Cardigan Bay parallel to the Llyn Peninsula for about 20km (12.4 miles).

Another, shorter reef is Sarn Gynfelyn north of Aberystwyth. Admiralty Sailing Directions (ASD) from 1870 said the pair presented formidable obstacles to shipping.

They also describe how onlookers might perceive Sarn Badrig as a weir in the sea. "For any vessel embayed between it (Sarn Badrig) and the Sarn Gynfelin in a westerly gale, escape seawards is quite hopeless," they said.