Mackerel skies and mares’ tails

Not a mackerel sky or mare’s tail, but a rather rare ‘roll cloud’ that we saw after Christmas as we drove home from Texas to Ohio. A roll cloud, or volutus, is a kind of arcus cloud, and is “a solitary wave called a soliton, which is a wave that has a single crest and moves without changing speed or shape”.

It was really very impressive.