Optical illusion turns Glen Affric hills into icebergs

A hillwalker says she was stopped in her tracks by the sight of an unusual mirage in the Scottish Highlands.

Claire McCorquodale was taking in views from Beinn Dearg when she saw the distant rounded hills of Glen Affric appeared to look like icebergs.

The Hostelling Scotland chairwoman said: "It was unsettling at first, as I couldn't understand what I was looking at.

"It was a clear day with a beautiful blue sky and it was very cold, about -5C."

It is suspected the iceberg effect was caused by an optical illusion called Fata Morgana, a mirage usually seen across open water and also in Arctic regions.

It makes objects on the horizon look like they are floating in the air.

In the past, the phenomenon inspired legends of fairy castles, mysterious cities and phantom ships.

BBC weather presenter and meteorologist Simon King said conditions when it was spotted on 26 February were ideal for a mirage.

He said: "Fata Morgana is normally seen on cold days and when there’s a strong temperature inversion – a sudden change one to two kilometres in the atmosphere.

"Caused by high pressure and separating two different air masses, the inversion acts like a mirror, so from the ground if you’re looking a long way to the horizon, light will bend and reflect.

"If the bending is more than the curvature of the earth, then the light coming to our eye has been bent, distorted and inverted creating the phenomena."

Garry Nicholson, forecaster and project manager of the Mountain Weather Information Service, said mirages could be seen at any time of the year if the conditions were right.

He said Claire's image of Glen Affric was a fascinating scene.