One of the most beautiful sunsets ever photographed in the Maltese Islands at Wied iz-Zurrieq due to volcanic ash drifting from Mount Etna towards the Maltese Islands as indicated by the visible satellite image on the fourth thumbnail. This is also classified as a lithometeor in the form of upper-level volcanic haze since the drifting “cloud” was actually composed of dry particles being ash and sulphur dioxide gas emitted from the volcano. If any rain fell on the day, it would have been sulphuric acid precipitation since water vapour reacts with the aforementioned gas leading to corrosiveness. The weather sounding and the surface pressure chart on the third and fifth thumbnails respectively show the state of the atmosphere over Malta during that afternoon and the surface wind circulation between the two homogeneous high pressure systems one over the Alps and the other over North Africa. The small cumulus clouds had occured due to a steep lapse rate at the surface whilst the ash drift was the result of an elevated NNE wind at 2000 metres being roughly at the same height of Mount Etna summit.

A very interesting feauture which could be observed on both the main image and the second thumbnail photos is that the ash was arranged in wave-like feautures similar to the undulatus cloud species. In fact, the mechanism for this was exactly the same as undulations in normal clouds whereby directional wind shear from a WNW wind to NNE was occuring between the surface and higher up. The first thumbnail proves that the “clouds” were actually sulphur dioxide gas obscuring the low angle sun which in fact led to a slightly colder day than expected. More photos of this event could be provided upon request.