What is the name for clouds shaped like a stack of pancakes?
Well known over the Canadian Rockies, these smooth, symmetrical clouds are known as altocumulus lenticularis, or lens-shaped clouds. They are also called mountain-wave clouds, because of how they form when winds rise to go over a mountain. As strong wind encounters a range of mountains, it is deflected up the windward slope and then down the leeward slope, and in doing so creates a gigantic wave or ripple that extends for several kilometres. Moist air, upon entering each wave crest, cools in ascent and turns cloudy, and then as the wave descends, it warms up and turns clear. It’s not just their appearance that makes these clouds so interesting and striking. While most clouds drift with the wind, these lenticular clouds seem motionless even though the wind is rushing through them. Groups of these clouds floating along in formation have led to reports of a fleet of alien UFOs swooping down from the heavens.
