Friends of Mary Louise Enser (Member 54,408) went to the Columbia River Gorge in Washington State, US on a sunset mission to photograph a shawl hand knitted by Cathy Swider, who Mary’s known since childhood.

As the Sun dipped below the horizon, the Altocumulus perlucidus clouds turned orange, pink, and grey – the very colours of the yarns in Cathy’s shawl. The darker patches of Altocumulus were where the cloud was in shadow, on the parts facing away from the setting Sun. The bright deep orange shows where the last rays were still shining up onto the cloud bases. The pale pink tones between the gaps show higher patches of Altocumulus. At sunset or sunrise, higher clouds always look paler, and lower ones have deeper, more intense hues. This difference in tones shows that the Altocumulus was at two distinct layers, which we describe as Altocumulus duplicatus.

To avoid confusion, the sky is the image on the left and the shawl’s the one on the right.