I have seen such a tail of clouds a couple of times, along the coast line in Sweden.
In Sweden, there is a peninsula called Kullen. It’s a big chunk of cliff on the western coast, not too far from Denmark. We went there to stay at “The Grand Hotel” in Mölle. The hotel is amazing. It sits high on the cliff like a Queen and has a fabulous view of the ocean and small harbor of Mölle, from where this photo is shot.
In 1908-9 The Grand Hotel was built as one of the first bathing hotels. People went there and bathed (shamelessly I might add) in striped long legged bathing suits. This shameless bathing caused photographers to go there and shoot photos of almost naked people (doh!), something that later turned into a valuable historic source of information about the early 20th century.
This photo is from the harbor in Mölle and you see Kullen on the right hand side. The light you see on the coast line is Ellens Cafe – a cafe worth a visit!