Cirrostratus
§ Cloud base at 6000 m or higher
§ A very thin layer of cloud composed of small ice crystals
§ Usually light white in colour and translucent to sunlight
§ Looks as if the sky is wearing a semitransparent veil
§ The outline of the sun and moon can be clearly seen through it
§ Can cause white or coloured rings around the sun or moon (a phenomenon called halo)