There is a strange not well documented weather phenomenon in Europe. I have only ever seen it 3 times in my life. It happens when the Sub Saharan winds blow north across the Mediterranean and hit the mountain ranges between Cantabria and the Pyrenees. I have seen it once in Spain and twice in France. There are no words to describe the skies, they become other worldly. If anybody knows more about this or can get some pictures please do post.
