The photographed cloud is surely Cirrus but it may alternate between floccus defined as `Cirrus in the form of more or less isolated, small, rounded tufts often with trails. The apparent width of the tufts, may be smaller or greater than one degree when observed at an angle of more than 30 degrees above the horizon` and spissatus defined as `Cirrus in patches, sufficiently dense to appear greyish when viewed towards the sun: it may also veil the sun, obscure its outline or even hide it. Cirrus spissatus often originates from the upper part of a Cumulonimbus.` The weather sounding indicated lots of upper-level moisture during that afternoon combined with wind shear as wind speed increased rapidly between 3000 metres and 4800 metres above sea-level. This cloud formation might have been triggered by the tail-end of a cold front that was about to pass over the area later that day. More shots of the high-level clouds can be observed by clicking on the following thumbnails.