Shafts of very isolated rain shower probably reaching the ground (would be Cu virga should rain haven`t reached the ground) due to an upper level cold pool of air centered over the Maltese Islands acting as a foci for convective activity on the day. Formation of Cbs was indicated on the weather sounding (which Malta did indeed have during the day) but waterspouts were unlikely to have occurred due to the clouds not likely to have being tall enough to profit from the shear in wind higher up in the atmosphere. The photographed cloud would have been much more beautiful during sunrise or sunset.