卷雲, or "cirrus clouds," are high-altitude clouds that form at altitudes of 5,000 to 13,000 meters. They appear wispy and thin, often resembling delicate strands or feathers. These clouds are composed of ice crystals and typically indicate fair weather, although they can also signal an approaching storm. These clouds are part of the cloud classification system and are categorized as high-level clouds. Their presence can affect the weather by indicating changes in atmospheric conditions. Observing卷雲 can help meteorologists predict weather patterns and changes in the sky.