photo #6167506

While driving through Queenstown, New Zealand, Alex Lancaster (Member 59,061) spotted a gigantic stack of lenticularis clouds. This disc-like species of cloud can develop at low, medium, and high levels. The lower ones here would be called Stratocumulus lenticularis. The upper ones, Altocumulus lenticularis. This cloud shape results from atmospheric waves that develop as stable air flows over hills or mountains. Where the air rises at the peaks of the undulating flows of air, it can cool enough to form clouds shaped like discs or lozenges. They appear stacked up in a pile like Alex’s, a form known as lenticularis duplicatus, when the airstream consists of alternating layers of dry air and moist air. This effect is sometimes also described as pile d’assiettes, French for a ‘stack of plates’. It is a pile of crockery left over by feasting giants, and we don’t envy whoever has to do the washing up.