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I have captured for La Vanguardia Readers’ Photos these views of the Sau reservoir, in Osona, which is almost empty. We can see the snow-capped Pyrenees, the emblematic Pedraforca and the low fogs forming a beautiful Brocken spectrum in a cold environment, with thermal inversion as well.
You can also see the abysses of Tavertet. This elevated municipality in the Collsacabra area has splendid views of the Sau and Susqueda valleys.
The Brocken spectrum can be observed on the opposite side of the sun, like the rainbow, but with the colors inverted. The reason why it is called that is found in Germany, where, as occurs in the Osona region, frequent fogs occur on the Brocken, a peak of the Harz Mountains.
The Brocken specter was observed and described by Johann Silberschlag in 1780. And, since then, it has often been recorded in German literature when talking about, for example, the devil and witches.
Fog is a meteorological phenomenon that consists of the suspension of very small water droplets in the atmosphere or of moist hygroscopic particles, which reduce horizontal visibility to a distance of one kilometer or more.
If the meteorological phenomenon gives a vision of 1 km or less, it is considered fog; and if it allows you to see more than 1 km, the phenomenon is fog.
The Osona region is the area of ??Spain with the most days of fog per year, approximately one hundred, making this meteorological phenomenon an intrinsic part of this area of ??Catalonia.
In one of the images we can see one of the effects of thermal inversion, which does not allow the smoke to rise more than the fog and there comes a point when the column of smoke is deflected downwards.
From this viewpoint in Sau we can see the snow-capped Pyrenees and the emblematic Pedraforca, which has a very peculiar shape due to its two peaks separated by a large hill, which gives it its name.
The northern summit is composed of two peaks: the Pollegó Superior (2506 m) next to the Calderer (2505 m). The south is formed by Pollegó Inferior (2445 m).
