Those who love mountain climbing may have observed a strange and startling phenomenon: a shadowy, almost ghostly outline of a person magnified by a misty halo around it. This seemingly supernatural experience is called a Brocken Spectre or a Brocken Bow – a climber standing in front of a low sun on a ridge or peak on a misty or foggy day.
Though a Brocken Spectre may appear huge because of fog and the glory obscuring its dimensions, it is merely the shadow of a person seen in the mist – usually one’s own – converging toward the antisolar point and coinciding with a glory (a rainbow-coloured halo produced by light backscattered through a cloud of water droplets).
To see a Brocken Spectre, specific weather conditions need to be met: the observer must be with his or her back toward the sun, for example in high-mountain areas where the sun is low. Many water droplets must be suspended in the air where the Spectre’s glory appears. Through diffraction, sunlight reflects off water droplets and shines back toward the sun and the observer, in these cases even two or more:
By the way, the name of the phenomenon is not a misspelled version of “broken spectre” but refers to the German mountain the Brocken, the higest peak of Germany’s Harz region. The Brocken is also the place where on Walpurgisnacht, witches are said to congregate in high numbers.
The Brocken Spectre was observed and first described by theologian and natural scientist Johann Silberschlag in 1780. Since then, several records of the phenomenon have been kept in regional literature about the Brocken.
But the phenomenon is by no means restricted to Germany; Brocken Spectres have also been observed at many moutainous regions Ireland.The photos above were taken in the mountains of Kerry and Waterford.