This spectacular, multi-hued formation of so-called lenticular clouds was observed over Rocky Mountain National Park, near Estes Park, Colo. Professional photographer Richard H. Hahn snapped the magnificent view soon after sunset at 5:02 p.m. MST (7:02 EST) on Jan. 5.
Lenticular clouds form when waves of moist, fast-moving air are pushed upward by winds and ascend over high mountains. At the mountain's higher altitude, the moist air's water droplets cool and expand, and the water vapor condenses. When the air moves over the mountain top and descends to uniformly humid air conditions, lenticular clouds form.
These clouds are characterized by their smooth, symmetrical oval or round shapes, and because of this, are often referred to as "flying saucer" or "UFO" clouds.
"The significance of this particular atmospheric event was the dramatic shape and color of the cloud. It really did look like the 'mother ship' UFO," Hahn told LiveScience.com. "It was ominous and breathtaking."