These clouds had formed on the cooler side of a highly undulating jet stream or planetary waves as they are known. The warm and strong upper level winds had flowed over a cooler airmass leading to the formation of this type of high-level cloud. Upper-level moisture is not evenly distributed hence resulting in fine fibers at the end of the photographed cirrus clouds where moisture is highest. Such clouds like to form especially during evenings as temperatures adjust according to its moisture content. At an altitude of more than 8.5km as indicated in the weather sounding, these clouds managed to make the day`s sunset over Malta especially spectecular due to reflection and refraction from the cloud`s ice crystals as evidenced by the first 2 thumbnails. The final thumbnail shows the jet stream winds which were most probably responsabile for this spectacular cloud display.