The Lough That Changes Colour

About twelve thousand years ago, when the last great glaciers were grinding their way through the Mourne Mountains, a tongue of ice carved a bowl into the granite between two of the highest peaks. When the ice finally retreated, it left behind a hollow — a corrie, in the language of geology — and the hollow filled with water. Clear, cold, mountain water. They call it Loch Gorm in Irish. The Blue Lough.

It sits at roughly 340 metres, cupped between Beann Each (Slieve Binnian — ‘Peak of the Horses’) to the north and Sliabh Lamagáin (Slieve Lamagan) to the south. Granite crags rise steeply on three sides, scree slopes tumbling down to the water’s edge, and the whole place has the feel of a natural amphitheatre — a vast, silent auditorium where the only audience is the sky.

The lough’s name tells you what to expect, but it only tells you half the story. Loch Gorm — the Blue Lough — can indeed be a striking, vivid blue on a clear day, when the sky is reflected in the still surface and the granite beneath gives the water a luminous quality. But come on an overcast afternoon, or when the clouds are low and the wind is pushing across the surface, and the lough turns dark — almost black, brooding, the colour of deep slate. After heavy rain, it takes on a greenish tinge. At sunset, it burns amber and copper.

Photographers love it for precisely this reason. The same walk, the same vantage point, will give you an entirely different lough depending on the day. It is one of the most photographed spots in the Mournes — for those who make the effort to get there. And that is the key point. Blue Lough is not roadside. It is not a quick stop on the way to somewhere else. You walk to it, climbing steadily through the Annalong Valley (Áth na Long — ‘the ford of the ships’), and the walk itself is part of the reward.

Most people approach from Carrick Little car park, a small gravel car park on the Head Road above Áth na Long (Annalong). From there, you follow a path south-west into the Annalong Valley, tracking the river upstream as it cuts through bog and rough grassland. The mountains close in around you — Slieve Binnian to your right, Slieve Lamagan ahead, the Mourne Wall snaking along the ridgeline above. After about 4 kilometres of steady walking, the path steepens and the lough appears below you, tucked into its granite bowl like something hidden on purpose.

There is a moment, about three quarters of the way in, when you crest a rise and the lough is suddenly there beneath you. If you have timed it right — a clear morning, low sun, still air — the water is an impossible blue against the grey granite, and the reflection doubles everything. You will stop. Everyone stops. The scramble down to the water’s edge takes another ten minutes, but by then you have already decided this was worth the effort.