Dente de cão
Explains the Madeiran expression 'dente de cão' for thin crystalline frost or rime appearing in the mountains after severe cold, mainly above 600–700 metres on the north coast.
In Madeira this name, dente de cão (‘dog’s tooth’, popular name for crystalline hoar frost), is given to the thin layers of crystalline snow that appear in the mountains after severe cold. These layers of snow result from the rapid freezing of water vapour on contact with the objects on which they appear. Frosts or dente de cão usually appear on the north coast above 600 or 700 metres, but on the south coast we believe they are unknown within the limits of the cultivated zone. When there is biting and prolonged cold, country people are wont to say that dente de cão is falling.