I was musing last month about altocumulus cloud on the Lincolnshire coast. I photographed this at Loch Ness. You can clearly see that there are two cloud layers and that the rippled layer is the higher of the two. The wind was moving in different directions in the different levels and at times it was hard to tell which layer was moving. The lower cumulus layer was just above the highest local mountain and so might have been 800 to 1000m. Altocumulus is between about 2000 and 6000m.
