photo #5512739

Rounding the corner of a mountain road in Canmore, Alberta, Canada, Louise Erskine (Member 61,879) was greeted by this smooth curve of cloud illuminated by the sunrise. This is an Altocumulus lenticularis cloud. It formed as a moist airstream lifted to pass over the mountain peaks. In stable atmospheric conditions, such airflows develop wavy paths, rising and dipping downwind of the peaks, with lenticularis clouds appearing at the invisible crests. When the wind speed is steady, lenticularis clouds appear to hover in place in the sky – as if they’ve stopped to admire the view like Louise did.