I took these photographs on the Lincolnshire coast. The wind was blowing from the land onto the sea. A bit of research suggests that the most likely cloud type is altocumulus undulatus. http://en.wikipedia.org/wiki/Altocumulus_undulatus_cloud The ribbed pattern is so regular that I was wondering whether it was a stationary wave pattern, but the whole pattern was moving across the sky. That suggests that the pattern was fixed when the clouds were formed. I haven't found a perfect explanation yet but they are talking about shear forces. Shear is tearing - forces pulling across something. The first picture, taken through a polarising filter, shows that the winds higher up were to some extent crossing each other because the ripple patterns are crossing each other.
