PHOENIX — Have you seen clouds that look like something from another world?
No, it's not aliens or UFOs, there is a scientific explanation for these cloud formations that look like flying saucers. 12News meteorologist Ginger Jeffries explains how these unique clouds are formed.
What are they called?
Altocumulus Standing Lenticular (ACSL) or Altocumulus Standing Lenticularis clouds, "Lenny" for short, result from waves and wind in the atmosphere.
These giant saucer-looking formations, have smooth edges, are oblong to circular in shape, and form above mountain ranges from desert climates to islands in the middle of the ocean.
How they form
The clouds develop when fast-moving air is forced up and over a topographic barrier (or mountain) that is in some degree perpendicular to the direction of the upper-level wind.
This deflection creates a gravity wave cloud. As that airflow falls and warms on the other side of the mountain, wind once again sculps the formation into a smooth rounded edge. The end result is a lenticular cloud seemingly stationary atop a mountain.
May have sparked UFO craze
These clouds are believed to have sparked the UFO craze in the 1940s when a pilot reported seeing "saucer-like" formations flying in an "echelon" fashion above Mt. Rainier in Washington. Some believe the pilot simply witnessed lenticular clouds due to the windy conditions reported in the area.
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The free 12News+ app from 12News lets users stream live events — including daily newscasts like "Today in AZ" and "12 News" and our daily lifestyle program, "Arizona Midday"—on Roku and Amazon Fire TV.
12News+ showcases live video throughout the day for breaking news, local news, weather and even an occasional moment of Zen showcasing breathtaking sights from across Arizona.