What visual phenomenon is associated with cirrostratus clouds?

Cirrostratus clouds are a type of high-altitude cloud that often create a distinctive visual phenomenon known as halos. These halos occur because the ice crystals in cirrostratus clouds refract sunlight, bending the light and producing a circular halo effect around the sun or moon. This phenomenon is particularly noticeable when the sky is clear and the halos can be quite striking, appearing as a bright ring surrounding the light source.

In contrast, thick grey layers that obscure sunlight are more characteristic of lower, denser cloud types, such as stratus or nimbostratus clouds, which do not have the same refraction properties as cirrostratus clouds. An extensive layer of ice typically refers to ice accumulation, which is not a direct visual representation of cirrostratus formation. Heavy precipitation is also not associated with cirrostratus, as these clouds are primarily known for their thin, wispy structure and minimal precipitation, which generally occurs as light snow or drizzle rather than heavy rainfall or storms.