Cirrostratus clouds are thin, white clouds that cover the sky like a translucent blanket, are composed mostly of ice crystals, and form at high altitudes. These clouds form when moist air rises, expands, and cools in the atmosphere. These are mostly seen in winter and when Cirrostratus clouds slowly thicken and lower, it means that rain or snow is on the way, typically within the next 12 to 24 hours.
