E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
An indication of pack-ice or of a frozen surface by its reflection on the clouds. If the sky is dark or brown, the navigator may be sure that there is water; if it is white, rosy, or orange-coloured, he may be certain there is ice, for these tints are reflected from the suns rays, or of light. The former is called a water sky, the latter an ice sky.