How to recognize Cirrostratus
Cirrostratus can be so thin that the sky remains bright and objects still cast shadows. Its ice crystals often produce halo phenomena. The veil may have faint fibrous structure or look nearly uniform, with an edge that advances across the sky.
Typical level
High troposphere; about 5–13 km in temperate regions.
Main texture
Transparent whitish veil, smooth or lightly fibrous.
Optical clue
Halo phenomena are common, though not guaranteed.
Model label
Cs · output index 5
Field clues and lookalikes
- Check for a broad veil rather than separate wisps or cells.
- A halo is a strong clue, but avoid looking directly at the Sun.
- Altostratus is denser and greyer; the Sun often appears dimly through it without a halo.
- Thin Stratus is much lower and more fog-like.
Weather context
Cirrostratus may form in broad upper-level moisture and can accompany larger weather systems. Timing and outcome cannot be inferred reliably from a single frame.
Photography notes
Photograph away from the solar disc when possible and retain faint tonal differences in the veil. A halo may exceed the centered crop used by the model, so the full preview remains useful to you.